Physiology 335 2005

Test 1

Intro to Physiology

Cell Physiology

Nervous System

Question:
In the following scenarios you have a cell in each beaker that is at 300
mOsM of non-permeating substance.  Is the solution Hypotonic,
Hypertonic, Isotonic, hypo-osomotic, hyper-osomtic, iso-osomotic?  Will
the cell shrink, swell, or stay the same?

a) Add 150 OsM non-permeating substance
b) Add 150 OsM permeating substance
c) Add 300 OsM non-permeating substance
d) Add 300 OsM permeating substance
e) Add 450 OsM non-permeating substance
f) Add 450 OsM permeating substance

Answer:
a) Hypotonic, cell swells
b) Hypo-osomotic, cell swells
c) Isotonic, no change
d) Iso-osomotic, cell swells
e) Hypertonic, cell shrinks
f) Hyper-osomotic, cell swells

 

1.) What is the most likely mode of cell entry or exit for each of the following substances? Know why this is the case.

          a. cortisol – diffusion

          b. ethanol – diffusion

          c. water – diffusion or via aquaporins

          d. glucose – facilitated diffusion or secondary active transport

          e. acetylcholine - exocytosis

          f. bacteria – endocytosis (macrophages, neutrophils)

          g. Na+ – Na+ channels

          h. phenylalanine (amino acid) – secondary active transport

2.) Come up with a solution that would satisfy each of the following criteria.  Assume intracellular molarity to be 300 mOsm and the cell contains only Na+ and Cl- channels.

          a. hyperosmotic and isotonic – 100 mM aspartic acid and 150 mM NaCl

          b. isoosmotic and hypotonic – 200 mM glucose and 50 mM NaCl

(Know how hypertonic and hyperosmotic differ, isotonic and isoosmotic differ, and hypotonic and hypoosmotic differ as well)

Question:

Initially, a cell is floating in 1 Liter flask full of ECF, and it is in
osmotic equilibrium at 300 mOSm/liter.  If you then add a nonpermeating
solute to the solution in the flask, wil the following increase,
decrease, or stay the same?

____the osmolarity or the ECF
____ the tonicity of the ECF
____ the volume of the ICF
____ the osmolarity of the ICF

Answers:
increase, increase, decrease, increase

 

Problem & solution for the week. Describe possible ICF and ECF
states for these two (unlikely) scenarios: a. Hypertonic & hypoosmotic.
A solution: Non-penetrating membrane, cell is 250 mOsm, beaker contains
solute at 275 mOsm. b. Hypotonic and Hypoosmotic. Cell with
non-penetrating membrane is at 300 mOsm, beaker contains solute at 200
mOsm. Bonus: what happens to cell in the latter scenario? Volume
increases as cell sucks up water.

1) Define:

Afferent neuron

Efferent neuron

Sensory neuron

Motonueron

2) Draw out  an example of a monosynaptic reflex labeling all components defined above.

3) A monosynaptic reflex requires all of the following except:

a) acetylcholine

b) stretch receptors on Ia afferents

c) Ia afferent axons

d) an interneuron

e) a motoneruon

1) 

Afferent neuron

Efferent neuron

Sensory neuron

Motoneuron

2) See diagram 10-6 on page 317 in chapter ten of 9th edition textbook

3) An interneuron

1) What is the initial segment?

The initial segment of an axon, also known as the axon hillock is the "trigger zone" for action potentials, located at the very start of an axon adjacent to the soma. Electrical signals are generated in this region and then propagated down the axon. The initial segment has a lower threshold due to a high concentration of voltage-gated Na channels in the membrane. Therefore, the initial segment is extremely sensitive to small changes in the membrane potential. 

2) What is a a synpatic potential? What is an EPSP, and what is an IPSP?

A synaptic potential is a graded potential change produced in the postsynaptic neuron in response to the release of a nuerotransmitter by a presynaptic terminal. The nuerotransmitters may cause EPSP's or IPSP's. An  EPSP is an excitatory postsynaptic potential (depolarizing---> more positive). Usually activated receptors open channels for Na, K, and other positive ions. An IPSP is an inhibitory postsynaptic potential

(hyperpolarizing--> more negative). Usually activated receptors open channels for negative ions such as Cl.  (K channels actually open as well, but definitely NO Na channels are opened).

3) How does opening positive K channels cause a hyperpolarization?

The RMP of K is -90mV, and the RMP of a normal cell is -70mV. Therefore, given the opportunity, K will rush out of the cell, making it more negative and closer to the K's intrinsic RMP.

4) Axon terminals A,B, and C synapse close to the initial segment of neuron X. When stimulated, A generates an EPSP of 15mV, B generates and IPSP of 8mV and C generates an IPSP of 10mV. The resting membrane potential of neuron X is -70mV, and its action potential threshold is -60mV. Simultaneous excitation of neurons A,B, and C will generate...?

Hyperpolarizing membrane potential (no action potential)

Question:
Choose all that apply for the following
A. Efferent somatic
B. Afferent sensory
C. Preganglionic sympathetic
D. Preganglionic parasympathetic
E. Postganglionic sympathetic
F. Postganglionic parasympathetic


1.  cell body in the CNS
2.  Cell body in the PNS
3.  Synapse in chain ganglia close to spinal cord
4.  Synapse with the adrenal gland
5.  Have varicosities
6.  Synapse with skeletal muscle
7.  Synapse with organs

Answer:
A. 1,6
B. 2
C. 1,4
D. 1
E. 2,3,5,7
F. 2,5,7

Question:  When describing converging and diverging neurons, where would
afferent and efferent neurons lie?

Answer:  Afferent neurons would tend to be convergin neurons since they
are starting out as branches and converging on the CNS.  Efferent
neurons would be considered diverging neurons because they start out in
the CNS and branch out to their affected tissues.

Question:  What would happen to the resting membrane potential if
instead of K+ being in higher concentration inside the cell something
more positive (such as Ca2+) was found within the cell but at the same
concentration?

Answer:  Because the concentration is the same the concentration
gradient would not be affected.  However, due to the fact that Ca is
doubley charged the electrical gradient would cause the Ca to leave the
cell at an even faster rate or in greater quantity than K+.  This would
mean that either the RMP would be even more negative than a normal cell
or that twice as much Na would have to influx to cancel out the effect
and maintain the -70mV RMP.

Explain how sodium channels inactivate. Do Potassium channels inactivate? And at what rate does each voltage-gated ion channel open/inactivate/close?

At the peak of an action potential sodium channels become inactivated by a “ball and chain” which implants itself in the bottom of the channel. Potassium channels do not become inactivated, but open and close slowly. Sodium channels open and inactivate rapidly.

Question:
Regarding the autonomic nervous system....
1) ____________ is the branch of the autonomic nervous system that
deals with "rest &  digest"
2) _____________ is the branch of the autonomic nervous system that
deals with "fight or flight"
3) Parasympathetic nerves arise from ___________ and _____________
areas of the spinal cord
4) Sympathetic nerves arise from ______________ and _______________
areas of the spinal cord
5) In the parasympathetic system, the preganglionic fibers are
___long/short__________ and only use ________________ as a
neurotransmitter.
6) In the sympathetic system, the preganglionic fibers are
___long/short__________ and use ________________ and _____________as
neurotransmitters.

   Question:
2 electrodes are connected to an axon; the first is 2mm away from point
x on the axon, while the second is only .5 mm away. If they both emit
an electric pulse of the same intensity, will their subsequent graded
potentials be the same? if not, which will be larger and why?

Answer:

The second electrode will produce a larger graded potential because it
is closer to the point x and, unlike action potentials, they decrease
with distance from the stimulus site.

Question
When the ciliary muscles contract which of the following occur?

a)zonular fibers have higher tension
b)zonular fibers have lower tension
c)lens becomes more spherical
d)lens becomes flattened
e)the eye opens

Answers
B, C

 

When focusing on a near object for an extended period of time (ie.
reading) your eyes get tired so you know that your ciliary muscle is
contracted and your lens needs to be more spherical.  For it to be more
spherical, you would want less tension in the zonular fibers. (This was
the logic, my group came up with to remember the system.)

QUESTION:
What are the four types of pathways leading from a neuron to a target
involving neurotransmitters and receptors?

**Draw CNS, PNS, and each pathway.  Make sure to label each part and
show distinct differences.**

**Have four people each take one pathway to draw on the board**

1. Somatic = one long nerve fiber releasing Ach to a muscle cell with
N-Ach Receptors
2. Parasympathetic = long preganglionic fiber releasing Ach to a
postganglionic cell with N-Ach Receptors; short postganglionic fiber
releasing Ach to a target with muscarinic receptors
3. Sympathetic = short preganglionic fiber releasing Ach to a
postganglionic cell with N-Ach Receptors; long postganglionic fiber
releasing norepinephrine to a target with adrenergic receptors (alpha,
beta)
4. Back up system = nerve fiber releasing Ach to the adrenal medulla
with N-Ach Receptors; adrenal medulla releases epinephrine into the
bloodstream

QUESTION:
1. Draw a typical neuron with cell body, dendrites, axon hillock,
axon, axon terminal, myelin, and nodes of Ranvier labeled.

Use "x" to mark ligand gated channels.
Use "v" to mark voltage gated channels.
Use "c" to mark calcium channels.

After labeling channels, explain what the purpose is for each type.

Ligand = cell body, axon terminal (reuptake of neurotransmitter); uses
chemical or any type of molecule to open channel
Voltage = nodes of Ranvier, axon hillock; requires a certain voltage
to open channel
Calcium = axon terminal; calcium channels open to allow calcium into
the axon terminal so that vesicales bind to the plasma membrane and
release neurotransmitter

2. Describe the terms IPSP and EPSP.  What does it mean when a
response is inhibitory vs. excitatory?  What types of
neurotransmitters are associated with inhibitory responses? 
Excitatory responses?

IPSP = graded potential, neuron falls below membrane potential - it's
hyperpolarized
EPSP = graded potential, neuron rises above membrane potential - it's
depolarized, but potential still below threshold

Inhibitory neurotransmitters = gaba, glycine, serotonin
Excitatory - acetylcholine, dopamine, norepinephrine, epinephrine

Problem:  My questions for the week concern being able to apply what we
know about the differences between rods and cones to some real-life
situations:

Question:  When you stare straight at a star for a while, why does it
seem to disappear?
Answer: It seems to disappear because (assuming you are in the dark
while you are looking at a star in the night sky) when you are in dim
lighting, you use your rods, not cones, to see.  Rods are located in the
periphery of your eye so they are unable to "see" things you are looking
at straight ahead of you.

Question: Why does everything in a dimly-lit room appear to be in
gray-tones?

 

Answer:  Again, rods are used when you are in dim lighting, and rods
have no color vision so everything appears without color, or in gray-tones.

Question:
My students were having problems converting units so I made some problems...
If you have 125 L/day, how many ml/s is this?

How many seconds are in two weeks?

You have 25 gibs/jeebs.  How many zibs/zeebs is this?
You are given:
2 jeebs=1 beeb
1 pib= 3 jibs
4 beebs = 6 zeebs
1 gib = 4 pibs
3 jibs = 7 zibs

Answers
1) 1.45 ml/s  (125 L/day)(1000 mL/L)(1day/24hrs)(1hr/60min)(1min/60s)
2) 1209600 s(2weeks)(7days/1week)(24hrs/1day)(60min/1hr)(60s/1min)
3) 933.33 zibs/zeebs
(25gibs/jeebs)(4pibs/1gib)(3jibs/1pib)(7zibs/3jibs)(2jeebs/1beeb)(4beebs/6zeebs)

Question:
What are the resting membrane potentials of K, Na, and the cell? 
Which of the ions is the resting membrane potential of the cell
closest to?  Why is located here?  Why isn't it equal to the ion it's
closest to?  What causes the membrane potential to occur?

K: -90
Na: +60
cell: -70

It is closest to K.  It is located here  because there are leak
potassium channels that allow K to flow down it's concentration
gradient (which is out of the cell).  It is not equal to K's resting
potential because some sodium channels are open in the resting state,
so the membrane potential is raised slightly.  The membrane potential
occurs because of the MOVEMENT of ions across the membrane, not the
number of charges inside or outside of the cell.

Problem:

We did a variety of small exercises.   First, I asked them questions about sensory receptors:

Sensory Receptors

1) Type determined by:

2) Duration determined by:

3) Stimulus intensity determined by:

4) Location determined by:

Answers: 1) receptor design, 2) signal (whether it is phasic or tonic), 3) AP frequency, 4)size and density of receptive fields

5) Draw how to correct for near-sightedness

6) Draw how to correct for far-sightedness

5 and 6) answers on page 48 of study guide

7) What happens in normal vision when looking at far objects?

Answer: Ciliary muscle relaxes, zonular fibers tensed

8) What happens in normal vision when looking at near objects?

Answer: Ciliary muscle tenses, zonular fibers relax

Question:

        I made this chart on the board (except did not fill it in first!), and had everybody fill in different parts.

Problem:

There are two cells with an anion named X^-.  For both cells, E_x- = - 70 mV.  For both cells, there is a much higher concentration of X^- on the outside of the cell.  In the first cell, Cell #1, the rmp is -90 mV.  In the second cell, Cell #2, the rmp is -60 mV. Which way will X^- move (i.e. - in or out of the cells) in Cell #1, and which way will X move in Cell #2?

Answer:

Cell #1: X^- will move out of the cell because the membrane potential is trying to reach - 70 mV.  Therefore, X^- needs to move out, which can cause the resting membrane potential to increase, and in an ideal situation, it would reach -70 mV.  (I realize this is a simplified way of thinking of it)

Cell #2: X^- will move into the cell because the membrane potential is trying to become more negative.  Thus, X^- needs to move into the cell, which will cause the membrane potential to decrease.  Once again, in an ideal situation, the rmp would reach -70 mV.

what is the difference between a graded potential and an action
potenta.  Include how both of them work 

an grades potential i think of as a stimules so when someone taps you. 
therfore it makes sense to say that they are proportional to size of
the stimulus (the harder someone taps you the greater potential)
cecrease with distance from the stimulus sight (if someone taps your
arm your toes dont hurt)
can  be depolarizations or hyperpolarizats and can summate with
eachother. 
are short distance (again tap you as the stimulus only get that much)
graded potentails are all or none.  I like to think of this as actually
at the cell body.  we are no longer thinking of a stimulus but
specifically.  this helps keep the two of them apart. 
action potentials are all or non.  the are not greaded by a stimuls
size and the cannot summate. so when it happens its done.  so how could
more happen?
thse are long distance.  like a wave in a pool it keeps going. 
the main differences is actoin potential is usually the influx of
sodium that builds up ot more and more and finally cross the threshold
do to some other neauron or signal. 

graded potentials start out different in the way a stimulus will cuase
the start of the reaction.

1.) Explain the principal behind how aspirin, opiates, and acupuncture therapies work to control pain.

          Aspirin works to control pain primarily through blocking the synthesis of prostaglandins (substance P) released from afferent nocireceptor neurons.  Opiates, both produced by the body and those that are synthetic work by binding to opiate receptors near afferent synapses which block the release of substance P from the neuron.  Acupuncture works by stimulating the release of the body’s opiates producing natural analgesia.

1.) Create a chart where you compare and contrast both graded potentials and action potentials.  Include relevant data such as magnitude, depolarizations or hyperpolarizations, summation, whether or not it experiences a decline in strength with increasing distance, function, and channels involved.  Feel free to include any other information you feel is important and would like to share during our discussion.

 Which would be more effective as a lethal injection into the bloodstream: a large amount of potassium or an equal amount of sodium?  Give a detailed mechanism for how it would work. (Strang study guide Fall 2004)

-          Injecting a large amount of K+ into the bloodstream would be more lethal.  This is due to the principle of resting membrane potential that depends on a small amount of K+ contained outside a neuron opposed to the inside.  By increasing the molarity of K+ outside the cell, the resting membrane potential is increased and approaches 0 mV.  This results in uncontrolled action potentials, ultimately resulting in a heart attack

Physiology 335 Fall,  2006

Test 1 – Questions and Activities

Intro to Physiology

Cell Physiology

Nervous System

1.      Does contraction always involve shortening of the muscle?

a.       Go through eccentric and concentric muscle movements. 

b.      Does the muscle length always have to change?  If not, give an example of when this is true.

2.      Draw a sarcomere and put in all of the lines and zones (ex. Z Line, M Line, I Zone, etc)

3.      Explain the difference between a muscle fiber, myofibril, and myofilament.  Which is the largest in size and how do they correlate with one another?

4.      How do you feel you could have better prepared for the previous exam and how can you translate this to your next exam?

Demonstrate using a notebook/pencil/etc. an isometric contraction, and
isotonic contraction(eccentric and concentric) and explain why there is
a longer latent period for isotonic contractions.

17. What is the effect of increasing the load on a skeletal muscle fiber shortening velocity?

A.  Shortening velocity decreases with increasing load.

1. True or False: There is only one phosphate involved in muscle action.
   1. Will need to explain because I have not clarified the wording so that it makes sense
   2. Answer: FALSE.  There is both phosphorylation and hydrolysis.  Phosphorylation is required to cause electrical repulsion.  Without this repulsion, electrical attraction keeps the thick filament stuck to the backbone.  The electrical repulsion pushes myosin away from the backbone.  This will then attach actin.  If there is no phosphorylation, tropomyosin is not in the way, but the cross bridge is stuck to the backbone.  Phosphorylation occurs once while hydrolysis (involving    ATP à ADP + Pi) occurs for every cross bridge cycle.
2. What are two ways to relax smooth muscle?
   1. Phosphatase. Phosphatase dephosphorylates phosphorylated (active) myosin to inactive myosin
   2. Turn off kinase.  Kinase turns inactive MLCK à active MLCK.  Therefore, you need to turn off the kinase, which can be done by removing calcium.

Question:

In the chemical synaptic transmission, what are the presynaptic events,
postsynaptic events at excitatory synapses, and postsynaptic events at
inhibitory synapses.


Answer:

Presynaptic:
1. AP propagates to terminal
2. Ca2+ channels open
3. Ca2+ activates vesicle exocytosis
4. N.T. diffuses across gap

Postsynaptic Excitatory:
1. N.T. binds to receptor
2. Ligand gated channels open
3. Na+ flows through
4. Depolarization

Postsynaptic Inhibitory:
1. N.T. binds to receptor
2. Ligand gated channels open
3. EITHER K+ or Cl- go in



Question:

Demonstrate using a notebook/pencil/etc. an isometric contraction, and
isotonic contraction(eccentric and concentric) and explain why there is
a longer latent period for isotonic contractions.


Answer:

So what I wanted them to do with this question is to show that holding a
notebook with both hands at a 90 degree angle, and keeping it there,
that it is an isometric contraction because although the length isn’t
changing, they are still contracting their muscles.  To show an
eccentric contraction, they would hold the notebook the same way as an
isometric contraction, but the imaginary increase in weight would lead
to the arms dropping and the muscles lengthening=eccentric.  The
opposite would occur with a concentric contraction.  The muscles would
get stronger/book lighter and the arms would contract upward and the
muscles would shorten=concentric.

The reason the latent period is longer for isotonic contractions is
because for isometric, the force doesn’t have to exceed the load ever.
But for isotonic contractions, the force must exceed the load in order
for movement to occur, so it takes longer to generate this additional
force, thus the increase in latent period.  To increase the force, the
muscle must reach the correct # of cross bridges before the mechanical
event can occur.




Question:

What are the differences and similarities between smooth and skeletal
muscle, and where would you typically find smooth muscle in the body?


Answer:

Differences

1.Smooth has no sarcomeres
2.Smooth has dense bodies, and no Z lines
3.Smooth has single nuclei
4.Smooth has no troponin
5.Smooth needs phosphorylation

Similarities

1.Both need hydrolysis of cross bridge for activation
2.Ca2+ plays important role
3.Cross bridge cycling
4.Both have length tension curves, although they aren’t completely the same

-Smooth muscle is found:
    -Lining the GI tract
    -Urinary bladder
    -Cardiovascular system—blood vessels
    -Reproductive system—uterus

Which of these groupings is correctly placed from the largest motor unit to the smallest motor unit?

a) FOG<FG<SO
b) SO<FOG<FG ******
c) SO<FG<FOG
d) FG<FOG<SO
e) None of the Above

It dealt with contracting your muscles in an isometric position
with a 15 ound wieght.  As you steadily increased weight, the load
began to outweigh the tension.  What are the possible conditions of
the muscle.
    a)  The muscle would continue to contract
    b)  The muscle would no longer contract since the load outweighs
the tension generated by the muscle fibers
    c)  The muscle would lengthen
    d)  a) and c)
    e)  none of the above

d) being my correct answer.  Once I thought about it though, I was not
sure if it was right and therefore didn't want to give it to them.  So
we just had them go through the long process mentioned above and
suggested during the meeting.

1) What causes conduction failure in fatigue?  
        Ans:  the increase in extracellular K+ causes the cell to
depolarize and increase the resting membrane potential cuasing firing
even when relaxed and hence fatigue.

   2)What physiological reason would make the AP being smaller/shorter
than the twitch contraction important?
        Ans:  Without it being shorter/ the contraction being longer,
you would never be able to summate or generate enough force/stimulation
to generate tetnus.  The refractory period would hinder tetnus.  

As the muscle contracts what the changes in length of the A band, I
band, Z line, and H zone?  The I band and H zone both shorten while the
A band remains at the smae length.  The Z line doesen't lengthen or
shorten during contraction but is an anchor point for the other
proteins to grab on to.

I made a list of the events that occur from the action potential propagating down the motor neuron all the way through the end of the cross bridge cycle.  I then put all of the steps on index cards, shuffled the deck, and handed out all of the steps to the group members.  They worked together to assemble them in the correct order.  I also had them work on Dr Strang's drawing/project thingy, which, through laughter at the "awesome" drawings, was pretty successful!

There are 3 basic types of muscle fiber types what are they and what
are they distinguished by:
a)  Slow Twitch, Slow oxidative-glycolytic, Fast Glycolytic, actin
isoform
b)  Slow Twitch, Fast oxidative-glycolytic, Fast Glycolytic, energy
conversion
c)  Fast Twitch, Fast oxidative-glycolytic, Fast Glycolytic, myosin
isoform
d)  Slow Twitch, Fast oxidative-glycolytic, Fast Glycoltyic, myosin
isoform

Basically, I combined number 67, 68, and 69 from the study guide questions.

Person       A (length to muscle attachment)   B (length from A to end of arm)

C (weight)

1 2 cm 18 14

2 4 cm 25 28

3 6 cm 30 18

I then asked the students to calculate X (tension generated upward), the gearing ratio, and velocity of the arm moving upward if the biceps were shortened at a rate of 2 cm/sec in an isometric tetanus for each of the above people.

1. X = 140;  ratio = 10;  velocity = 20

2. X = 203; ratio = 7.25; velocity = 14.5

3. X=108; ratio = 6; velocity = 12T/F Cardiac muscle is similar to smooth muscle in that it is striated

False

 

T/F THe only mechanisms of Ca2+ entry into smooth muscle cells are
through strech sensitive channels and voltage senstive channels.

False

Question for the week:

If you are doing a wall sit, what type of muscle contraction are you performing? If you added a weight to your lap, would the type of contraction change?

The question our group set out to
answer this week was about how sacromere length can produce different
amounts if tension in the muscle when it is cross bridge cycling. 
There is basically a picture of it in the book, however i thought it
was important for the group memebers to have a solid understanding
about how it works.  So, to answer the question, i drew the graph up
on a board labeling the axis as percent of max isometric tetanic
tention vs muscle length, and drew the curve.  Next our group
discussed what the sacromer would look like at each point. 

 

question for this week was, “What channels and ions are involved in the action potential of an auto rhythmic cardiac cell?”  For this question, I had group members go up to the board and basically draw figure 12-13 from the notes and explain it to the rest of the group so that they knew what channels were affecting which section of the action potential graph and when.  For example, funny type Na channels and t type calcium channels contribute to the depolarization phase of the action potential. 

Question:

I had them fill out a chart about different methods of transport.  Here is the chart:

                      Ion Channels    Facilitated Diffusion    Primary Active Transport   SecondaryActive Transport

"Direction"        2way                 2 way                 1 way                                 1 way

"With or Against

Concentration        With                  with                        against (creates one)                       against

Gradient"

"Use ATP"         no                          no                         yes, direct ATP splitting                    indirect

"Examples"       Na+, K+, Cl-         Glucose                   Na+/K+ ATPase pump          Glucose and AA-                                                                                                                             co-transport (w/Na+)

Question:

In normal vision, if something is far away, cilliary muscles are (relaxed/contracted), and there is (tension/no tension) in the zonular fibers, which results in a (flattened/rounded) lens.

Question 1:

Based on what you’ve learned about membrane permeability you must design a drug/medication: What characteristics would be beneficial to include when synthesizing a drug/medication? Also, what happens to the cell after it is administered?

Hint: think about solubility, polarity, receptors, membrane proteins, size, types of junctions between cells, ionization, solubility, and pH

(Refers to study guide questions 25-38)

Question 2:

At equilibrium, when the neuron is at rest:

1. the concentration of K+ ions is the same on both sides of the neuronal plasma membrane
2. the concentration of K+ ions is higher inside the cell, but the diffusion force driving K+ ions out of the cell is balances by an electrical force keeping K+ from leaving the cell
3. sodium and potassium ion concentrations are the same on both sides of the plasma membrane

Question 3: 

1. Which of the following are true about the synaptic potential?

a. the Na⁺ and K⁺ currents occurs simultaneously

b. is a graded potential

c. the channel is ligand-gated

d. the post-synaptic potential is inhibitory when 
    depolarizing

 (all true except d)

Question of the Day:  Rigor Mortis is a stiffening of the skeletal muscles approximately 12 hours after
death. This is a result of…
a) The lack of movement and therefore absence of neural signals from the Nervous System regulating cross bridge cycling.
b) The contractile proteins, Actin and Myosin, become very rigid and inflexible post-mortem, and therefore inhibit any
movement
c) The decline in [ATP] in cells inhibit the breakage of the Actin Myosin link, and therefore, the thick and thin filament
cannot be pulled past each other. 
d) If you don’t need to move, why would your muscle fibers need to move?

I had them fill-in/write on the white board the location and type of
neurotransmitter released for the different parasympathetic and
sympathetic signals and also which kind of receptors were used in each
case.  - They said they found this helpful to go over, so that was good.

Physiology 335  2005

Questions Test 2

Muscle Physiology

Endocrine System

Problem and solution. Practice drawing sarcomeres marking with
labels for terms in study guide question 5. Draw these in relaxed and
contracted positions. Review changes in the widths of the various
bands, zones and positions of the lines.

Which of these play a role in muscle homeostasis (choose all that apply):
a. fidgeting
b. acquire nutrients/fuel
c. process food
d. breathing
e. walking
f. escape from harm
g. pH balance
h. generate heat
i. storage depot for amino acids

Answer: b,c,d,f,h,i ble to recieve optimal oxygen. 

1.) Why would it be beneficial for a golfer to be tall and slender rather than short and fat?  Likewise, why is a short stature much better for generating power?  Explain.  (hint: think in terms of gearing ratios)

It would be more beneficial to be a tall and slender golfer.  The reason for this is that a higher gear ratio will be obtained if the muscle is farther away from the fulcrum.  Therefore, a higher velocity, and thus, club head speed will be generated for the golfer.  Short stature evokes the opposite principle.  The gear ratio is much smaller, but more weight can be lifted because the lever action of the arm isn’t as great.

2.) Put the following steps for smooth muscle contraction in order and fill in the blanks in the descriptions.

__4__ MLCK is activated via binding to calmodulin

__1__ Smooth muscle is activated via _stretch____,  _a pacemaker cell_, _local (chemical)           factors_, _autonomic nerves_, or _hormones_.

__2__ Ca­²⁺ is released into the cytoplasm.

__3__ Ca²⁺ binds calmodulin.

__6__ Cross-bridge cycling/force

__5__ MLCK phosphorylates myosin, activating it

* Go over questions: 16, 17, 29, 30, 33, 38, 43, and 45.  We will need to go over these questions again based on information I obtained in my weekly meeting.

Question:  Tell me what receptors epinephrine and norepinephrine act on in the arterioles and the heart

Answers:

Arterioles:

E - alpha (cause vasoconstriction ), beta  (caues vasodilation)

NE - alpha (cause vasoconstriction)

Heart:

E and NE - beta (increases heart rate) - no alpha receptors in heart

Question:
Why do extreme dieters experience muscle loss?

Extreme dieters run out of glucose stores (glycogen),so the body has no
choice but to use glyconeogenisis to get energy.  Glyconeogensisis gets
this energy from breaking down amino acids in your muscle.

 

T/F  Capillaries are made up of smooth muscle

Answer: F

If capillaries lack smooth muscle, what causes them to contract and relax?

Answer: The don't contract themselves.  The volume of blood that the
capillary receives are regulated by upstream metarterioles and
precapillary sphincters

Problem: 

1. T or F  Muscle cells are multinucleated    (T)

2. Myofibrils are:
     a. the zone containing only thick fillaments at the center of the sarcomere.   (no- this is the H-zone)
     b. the functional unit of the muscle, boardered on both sides by Z-lines.  (no sarcomeres)
    A:  c. the force generating components on individual muscle cells, composed of actin and myosin. (yes)
     d. individual muscle cells.  (no, they are components of MC's)

3. The points of regulation on the thin filament (actin) are tropomyosin and troponin. Tell what each regulates. 
      A: tropomyosin- guards the binding site on actin to which myosin binds
      A: troponin- senses calcium which triggers/stimulated contraction.  It also controls the position of tropomyosin

4.  Define optimal length.

    A:   The optimal length of a muscle fiber is defined as the length at which maximal tension can be achieved.)

Match the following parts of a muscle cell to their functions:

1. Sarcoplasmic Reticulum

2. Troponin

3. T-tubules

4. Sarcomere

5. Lateral Sac

6. Tropomyosin

7. Sarcolemma

8. Calsequestrin

a)      Continuation of surface membrane that transmits action potentials into the microfibrils, triggering calcium release.

b)      Membraneous structure that receives and conducts stimuli; voltage-gated channels; regulates nutrient/waste entering and leaving the cell

c)      Actin-bound protein that is the site of the calcium binding that initiates muscle contraction

d)      Enlarged region at the end of each sarcoplasmic reticulum segment; calcium storage site

e)      A calcium binding protein that localizes calcium accumulated in the sarcoplasmic reticulum during relaxation

f)        The smallest unit of muscle contraction

g)      Network that action potentials pass through, releasing the calcium required for muscle contraction

h)      Regulatory protein in charge of allowing or preventing myosin connection to actin binding sites

Answers:  1) g

2) c

3) a

4) f

5) d  

6) h

7) b

8) e

draw a diagram and show were the three places that muscle fatigue
happen and why. 

conduction failure in tubules (lethel injections)
bilid up of hydrogen with the crosss bridges, and central command
fatigue. (they should have a picture that starts with an action
potential going to the brain and cross it out ot show central command
fatigue cross bridges  and t-tubles ..picuture should include the s.r.
calcium myosin, tripomysin, nerve ending and so on..)

how does skeletal muscle work starting from an action potential to muscle moving. 

first you get an excitatory action potental. Which allows ca2+ channels to open  which allows ach to be released
which ventures to the other side to nicotinc receptors which allows the influx of sodium which sends an action
potential to the dhp receptors which open the ryanodine recepotr which allows for the out flux of calcium which
binds to the troponin which moves the tropomyosin which exposes the actin which allows for the binding of the
myosin which has atp bind to it  which splits to adp and p whih  then comes off and channels uptake the
calcium. 

 Problem: I drew a table and had them each fill in a couple rows.  This was a good review exercise because they had just covered this material in class the day before.

Question:

Why is Botox dangerous?

The Botox injection is made from the botulinum toxin which blocks Ach release in the synapse of muscle
neurons.  This causes paralysis in muscle cells.  If given incorrectly it could cause paralysis in the face.

What do curare and gallamine do?  What is the difference between the two?

They both bind to ligand gated Ach receptor channels which keeps them closed so nothing can come in.
Gallamine can be used for local paralysis but curare is more general.

What is the effecct of pesticides?

The Ach degredation is blocked so Na channels are kepts open.  When kept open the channels get desensitized
and it causes temporary paralysis.

Cut out and mix these up and then have the students put them in the correct order.

AP travels down Sarcolemma
Sarcolemma depolarized
AP travels down T-tubule and depolarizes it
DHP receptor depolarizes
Ryanodine receptor pulled out
Calcium released from lateral sac
Calcium binds troponin
Tropomyosin pulled off actin
ADP+P cross-bridge binds to actin
ADP+P released
Power Stroke
ATP binds to myosin
Myosin detaches from actin
Calcium pumped into SR by Calcium ATPase pumps
ATP hydrolizes into ADP+P

True/False:  Rigor mortis is caused by an inability of ATP to hydrolized into ADP+P

FALSE

QUESTION:
1. Draw the following on the board: membrane of muscle fiber, t-
tubule, DHP, RR, SR, ATPase pump, NMJ (synapse), cytosol, ECF
a. Label the above with letters and then have group members take turns
finding the name of the structure corresponding to the letter.

2. Draw a sarcomere: Z line, M line, H zone, I band, A band
a. Don't have the lines or zones labeled on the picture but have group
members label the areas.
b. What areas shorten during muscle contraction? = H zone, I band
c. What areas stay the same during muscle contraction? = A band

Question: (may repeat when we actually meet)
Please correct what is false.

1. T or F If a muscle "contracts" it shortens?
2. T or F There are an equal amount of thick and thin filaments.
3. T or F Myosin heads have two binding spots.
4. T or F Calcium must be present to initiate contraction
5. T or F The thin filament consists of only actin and tropomyosin
proteins.

Answers
1. F When the muscle contracts crossbridges form but it does not mean
that shortening must occur (ie. when you hold a book muscle contracts
but does not shorten).
2. F There are twice as many thick filament than thin filaments.
3. T One site to bind ATP and another site to bind actin.
4. T Calcium binds troponin and allows myosin to bind actin
5. F Consists of actin, troponin, and tropomyosin

Questions:
T/F: All fibers in a particular muscle are of the same type.
    (Answer: False.  Most muscles contain a mixture of muscle fiber types)

T/F: All fibers in a particular motor unit are of the same type.
    (Answer: True.)

Q: What determines what type of muscle fiber a particular motor unit
will be composed of?
     (Answer:  The alpha-motor neuron that innervates the motor unit
decides what type of fibers that motor unit will contain)

Q: Where are the motor units composed mostly of the slower fiber types
most often found, closer or farther from the bone?
     (Answer: The slower types are found mostly deeper and closer to the
bone.  The faster ones are more superficial.)

*Problem:  I asked them some questions about the Isometric
Length-Tension graph.  First, I drew the graph without labels and had
them label it.

Question:

What is titan and why is it important?

Titan is a protein in the sarcomere of muscles.  Without it, the
muscle tissue would fall apart if it were stretched beyond its optimal
length, which is especially important if you hyperextend a a muscle.

T/F  Fiber type is determined by the alpha motor neuron
True

 

-Question: What happens to the H-Zone, A-Band, I-Band, and the distance
between the Z-lines at 70% and 130% lengths, as compared with the
resting muscle?

    Answer: 70%: The H-Zone, I-Band, and distance between Z-lines all
are smaller. The A-band is the same.
            130%: The H-Zone, I-Band, and distance between Z-lines all
are larger. The A-band is the same.

-Question: Why is there less force at 70% (or less) of muscle length? At
130% (or more)?
     Answer: At 70% or less, when the Z-lines hit the thick filaments,
an internal resistance is created which gives rise to less force.  Also,
if the muscle length is small enough, the thin filaments may overlap so
that the cross-bridges don't have access to the entire thin filaments.
At 130% or more, the H-Zone is wider, meaning there is less overlap
between the thick and thin filaments.  Again, there is less thin
filament available to the cross-bridges, meaning less force can be
created.  Also, as length increases, there is decreasing overlap between
thick and thin filaments which is why force decreases with increasing
length.

Question:

What is the key difference of initiation in smooth muscle contraction
compared to skeletal muscle contraction?

Answer:

The calcium complex is bound to the thick filament (myosin-calmodulin)
in smooth muscle contraction, while the calcium complex is bound to the
thin filament (actin-troponin).  ATP must bind for the degration of the
cross-bridge in smooth muscle which is why contraction can be held so
long and little ATP is used.

Questions:

1. Match the mechanical steps to the corresponding chemical steps of the cross-bridge cycle.

             Mechanical Steps                                                                             Chemical Steps

1a. Cross-bridge cycle rotates & pulls on the thin filament.                1b. Ca2+ rises in the sarcoplasm.

2a. Cross-bridge is energized to a ninety degree position.                  2b. ATP splits into ADP & Pi.

3a. Cross-bridge detaches from actin.                                              3b. ATP binds to the cross-bridge.

4a. Cross-bridge binds to actin.                                                        4b. ADP & Pi are released.

Answer:  Step 1:  4a and 1b

               Step 2:  1a and 4b

               Step 3:  3a and 3b

              Step 4:  2a and 2b

2. Skeletal muscle is a user.  What are three sources of ATP for skeletal muscle?

             Answer:  1.  Creatinine Phosphate - Rapid (but limited, only the first few seconds)

                             2.  Oxidative Phosphorylation - Aerobic (during moderate exercise)

                             3.  Glycolysis - Anaerobic (during high intensity exercises)

                            *Different fiber types use different mixtures of ATP sources.

Question:

Draw a sarcomere and then label the A-band, H-zone, I-band, Z-line,
M-line.  What are each of these composed of and do they change with
contraction?

Answer:
Figure 9-8 in the ninth edition Human Physiology book by Strang shows
all of this.
A-band         Thick filament                                                 No change
H-zone         Space between opposing ends of thin filaments         Reduces
I-band         Thin filament that does not overlap thick filament         Reduces
Z-line         Proteins that the thin filament anchors to                  No change
M-line         Central proteins that link the thick filaments                 No change

Question:  Explain the significance of the white color in fast-twitch
muscle fibers vs. the red color in slow-twitch fibers.  What metabolic
process comes into play during fast-twitch that accounts for this?

Answer:  the white color is present due to the lack of oxygen being
used with
fast-twitch contraction.  These fibers lack red myoglobin, and
therefore use glycolysis to genereate energy (anaerobic).  The red
color in slow-twitch is due to an abundance of red myoglobin.  The
longer, sustained contractions of these fibers is better suited for
oxidative metabolism, implying numerous mitochondria that present the
energy needed for long contraction periods.

Question: Label the following contractions as mostly fast twitch or
slow twitch:

a. contraction of the extraocular muscles of the eye
b. prolonged contraction of the back muscles while maintaining upright
posture
c. lifting a heavy object in a short period of time

Answer:  a. fast b. slow c. fast

Question:  If ATP wasn't able to bind to the myosin head what would
happen to the cross-bridge cycle?  Where and when would it break down.
If the phospate wasn't able to dissociate from the myosin head how
would that effect the cross bridge cycle.

Answer:  If Atp can't bind to the myosin head it won't be able to
dissociate from the actin polymer.  Thus after one power stroke the
myosin will be unable to be recharged.
If the phosphate can't dissociate from the myosin head after the ATP has
been hydrolosized the myosin will not be able to go through the power
stroke.  The myosin will move into the correct conformation but be
unable to actively pull on the actin.

Question:  Matching!
1.Functionaly similar to z lines.
2.Multiple cells acting as one
3.Stimulated by autonomic nervous system
4.Group of muscle fibers innervated by an alpha motor neuron
5.Has sarcomeres

a.skeletal muscle
b.synctium
c.dense bodies
d.motor unit
e.smooth muscle

Answer
1.(c) 2.(b) 3.(e) 4.(d) 5.(a)

Why do you experience a paralysis when you block the action of actylcholinesterase? 

The ligand channels are kep open causing a rapid entry of Na+.  This rapid entry causes continuous firing of AP's until the channels desensitize.  At this point, the channels close and are not able to open again.  Because the membrane repolarized due to the stopped current from the channels closing, no more AP's can fire and you are in paralysis. 

Question:  If you were to have an auto-immune disease that
destroyed muscarinic cholinergic receptors which portion of the nervous system would not function.  Be specific.

    Answer:  The postganglionic synapse of the parasympathetic system
which uses Ach as a neurotransmitter.

Question:  Fill in the blanks : 

Two sources of calcium contribute to the calcium that facilitates smooth muscle contraction, 1? and 2?.   When the calcium needs to be removed, the 3? transport of calcium back into the 4?? occurs, but at a much 5? rate than skeletal muscle.   The activity of smooth muscles is synchronous in a 6? unit smooth muscle.  One single stimulus conducts activity between fibers by the linkage of 7??.  Some of the fibers  spontaeously generate AP's, called 8? cells, (but we'll learn more about that in cardiac)  On the other hand, 9? unit smooth muscle has no or few linkages between fibers.  These fibers are innervated by many 10? branches of the nervous system. 

Answer: 1. sarcoplasmic reticulum
2. extracellular  calcium
3. active
4. sarcoplasmic reticulum
5. slower
6. single
7. gap junctions
8. pacemaker
9. multi  
10. more

Smooth Muscle  

No Sacromeres

Sarcomeres

Dense Bodies

Single Nuclei

Troponin

No Troponin

In Sheets

Small cells

Large Cells

No T-tubules

T-tubules

Minor Ca2+ stores

Gap Junctions (synctium)

Self-excitatory (pacemaker)

GI tract

Reproductive organs

Urinary Bladder

Small Blood vessels

No gap junctions

Autonomic Nerve Activated

Multi-Unit Muscle

Single-Unit Muscle

Large Blood vessels

Airways

Eyes

Hair Follicles

Peptides/Proteins

  aminoacids

Amines

Tyrosine

Steroids

Cholesterol

Catecholamines

Thyroid

Hydrophilic

Vesicle Storage

Soluble in blood

Extracellular receptors

Fast effect

Fast Metabolism/excretion

Hydrophobic

Membrane permeant

Need protein carriers

Intracellular receptors

Slow effect (synthesize proteins)

Question: What does muscle fatigue result from?

List for Aerobic and Anaerobic metabolism where it occurs, #ATP produced, type of muscle
fiber, waste, and rate.

Muscle fatiuge occurs, not due to ATP, but due to conduction failure in
the T-tubules, build up of H+, ADP, Pi and central command fatigue.

Aerobic: Mitochondria, Oxidative phosphorylation, 36 ATP; CO2/H2O as
waste and slow rate
Anaerobic: Glycolysis, Cytosol, 2 ATP, Lactic acid waste, fast rate.

Slow metabolism/excretion

Question: Which muscle type is striated and voluntary? Which is striated
and autonomic? Which is just autonomic? Where is each of the muscle
types found? Which are single nucleated? Multinucleated?

1) Skeletal, attached to bone, multinucleated
2) Cardiac, Heart muscle, single nucleus
3) Smooth muscle, GI, Airway, Blood vessels, stomach, single nucleus

Question:  Why is it important that we have slow oxidative fibers in our
body?  Would we be able to get by without SO fibers?

Answer:  Because SO fibers fatigue slowly, they are very important in
postural muscles.  If these weren't made of SO, we would have great
difficulty standing for any period of time or remaining in any position
that required us to contract our muscles.

Question:
When cross-bridge cycle and a muscle shortens, the relative positions of
the thick and thin filaments change.  Do the following become greater,
less or stay the same?
____distance between Z-lines
____ the width of the A-band
____ the width of the I-bands
____the width of the H-zone
____ the width of the M-line

Question:  Skeletol Muscel Fiber Types
     SO= Slow Oxidative
     FOG= Fast oxidative glycolic
     FG= Fast glycolic

SO muscle fibers are (higer/lower) than FG fibers in their myoblobin
content.

FG muscle fibers are (larger/smaller) in diameter than FOG fibers
FOG fibers fatigur(faster/slower) than SO fibers
The muscle fiber type which is lightest in color are (SO/FOG/FG)
SO fibers are (higher/lower in glycolytic activity than FG fibers
FG fibers have (more/less) oxidative enzymes than SO fibers
SO fibers have a (slower/faster) cross-bridge cycling rate than type FOG

answers: higher, larger, faster, FG, lower, less, faster

Question:
Which area of the body has larger motor units: the feet or the hands?
how can you tell?

Answer:
Motor units consist of 1 motor neuron and all the muscle fibers it
innervates.  The size of a motor unit determines the precision of
movement (i.e. a large motor unit has very imprecise movement).  Since
the hands are capable of such fine movement while the feet can only
produce gross type movement, the hands have smaller units.
 

Question:  Myoglobin is a molecule that has a structure similar to
that of one of the hemoglobin subunits.  Myoglobin, however, will
typically bind up to 96% of the oxygen it can carry in tissues with a
normal P02 level.  If the equation for percent saturation of myoglobin
is saturation = P02/(P02 + .26) what will be the level relative level
of saturation of myoglobin in oxygen depleted tissues?  What does this
say about myoglobin relative to hemoglobin?

Answer:  In oxygen depleted tissues there is a low p02.  Looking at
the equation then myoglobin would give up its oxygen in very oxygen
poor environments (i.e. low saturation).  Relative to hemoglobin,
myoglobin is a poor transporter of oxygen, but it is an excellent way
to store O2 until it is needed.

Question:  If MLCK isn't produced in the body what will this mean for
thin filament regulation?

Answer:  Nothing.  MLCK is activated by the calcium-calmodulin complex
which is responsible for activating myosin in smooth muscle.  This is
thick filament regulation.

Question:  A patient who is a 10 year old boy comes in with
hyperthyroidism.  When you walk in you notice that the boy is well over
6 feet tall.  What is a possible cause of the two disorders(a single cause)?

Answer:  The boy could have a tumor in either the hypothalamus or the
anterior pituitary gland that cause hypersecretion in both of the pathways.

 

Question:  What is the unifying cause of Goiter given the two
different pathways?

Answer:  The over expression or uncontrolled expression of TSH.  If
for example a tumor forms on the Ant. Pit. a large, continuous influx
of TSH will occur.  Because TSH is both a tropic and trophic hormone
the thyroid will grow uncontrollably and form a goiter.  However, if
T3 and T4 aren't produced by the thyroid or there is no receptor for
T3/T4 on the Ant. Pit. there will be no negative feedback loop.  This
means there will still be uncontrolled secretion of TSH also producing
a goiter.

Problem and solution. More about stress: increase plasma cortisol
results from what other hormone circulating in the plasma? [ACTH] Which
results from what other secretion(s)? [hypothalmic CRH, cytokines] Why
is the hypothalmic secretion not in high concentration in the general
circulation? Which secretions exert a feedback effect on the
hypothalmus? [ACTH, cortisol] What would happen if there were no
feedback? [Cushing's type symptoms]

Problem and solution. Reproduction: Just exactly what is responsible
for the two increases in estrogen levels during the menstrual cycle?
what are the effects of these increased levels?
The first increase is the release from the follicle. its effects are:
proliferation of the endometrium; other follicle "candidates" being
turned "off" by decreased LH and FSH; LH causes oocyte development and
release. The second increase is secretion by the corpus luteum. Effects
include: follicles are turned off; increased secretory activity of
endometrium to prepare for implantation.

Iodine Difference:

In iodine deficiency, T3 and T4 are not made because iodine is required for the synthesis of these hormones.  Because level of thyroid hormone are minimal, there is no negative feedback occuring and therefore, TRH and TSH would be high.  The overstimulation of the thyroid gland by TSH produces a goiter. 

In Grave's disease, theTSH recptor on the thyroid gland is stimulated by disfunctional antibodies.  As a result, the thyroid gland pumps out a lot of T3and T4, but this high concentration sends negative feed back to the hypothalamus and A. Pit, thus decreasing the TRH and TSH levels.  However, there is no way to turn off the thyroid gland stimulaiton from the antibodies so the gland is contantly overstimulated and a goiter develops. 

Question: Why does FSH rise and then fall between days 1 and 10? What
happens on day 24 of the cycle? Which gonadotropin causes ovulation? How
many chromatids per chromosome are present in a secondary oocyte? How
many during oogonia?

Answer: FSH spikes between days 1 and 10 because more than one follicle
is growing, up to 10 follicles can be growing at one time. FSH falls
when just one follicle is picked to release an egg on day 14.
Implantation occurs on day 24 if fertilization has occured. LH causes
ovulation.  There are 2 chromatids per chromosome in the secondary
oocyte and just 1 chromatid per chromosome present in oogonia.

Question:  Bobby has been short his whole life.  One day he overhears
someone talking about how growth hormone is a major factor in a persons
growth.  Bobby decides that he has spent the last 22 years of his life
being short and he is now going to do something about it by taking
growth hormone.  Why would taking growth hormone probably not result in
him growing taller and what could be some repercusions of taking it?

Answer:  Because Bobby is 22, his growth plates have probably fused and
he won't be able to grow any taller.  A side effect of taking the growth
 hormone could be that he developes acromegally if he takes the hormone
for an extended period of time.

Question:
1) all of the hormones secreted by the hypothalamus, pituitary gland,
heart, kidneys, thymus, digestive tract and pancreas are:
a. steroid hormones
b. amino acid derivatives
c. peptide hormones
d. catecholamines

2) A pituitary endocrine cell that is stimulated by a releasing hormone
is usually:
a. also stimulated by the peripheral hormone it controls
b. not affected by the peripheral hormone it controls
c. stimulated or inhibited by the peripheral hormone it controls
d. inhibited by the peripheral hormone it controls

Answers:
1) c
2) d

Q:   Based on what you know about the hormone insulin and its effects on the body, would you expect the compound to be hydrophilic or hydrophobic?  Why?  What about glucagon?

A.   Insulin is a hydrophilic compound, meaning it is fast-acting.  Insulin is released when plasma glucose levels are high, i.e. after a meal, in order to quickly pull the glucose into cells and return the concentration of glucose in the bloodstream to normal.  If insulin was a slow-acting hormone (hydrophobic) blood glucose levels would continue to rise higher and higher after every meal was ingested and body cells would have to resort to generating energy via fatty acid oxidation and gluconeogenesis (and negative symptoms similar to those caused by diabetes would occur).  Glucagon is also fast-acting (similar thought process but opposite implications).

Problem and solution

There is a ventilation-perfusion unequality in undiseased people due to
(give explanation)[the effect that upright posture causes uneven blood
flow in the lungs, because gravity increases the filling of blood vessels
in the inferior lobes.] The PO2 in arterial blood is [higher/lower] than
that in the alveoli.

Problem and solution
I have a theory that if you want more cut abs, do any kind of exercise
that makes you breathe pretty hard for extended periods; swimming for
instance would be good because one's breathing is exaggerated. Besides
extended exercise's weight-loss effect of catabolizing fat for fuel, what
other reason do I have to believe that this might be true? (abdominal
muscles are involved in expiration.)

QUESTION:
First, draw pathway for thyroid hormone: hypothalamus secretes TRH
which stimulates anterior pituitary to secrete TSH which stimulates
thyroid to secrete T3 and T4.  T3 and T4 have negative feedback on the
anterior pituitary and the hypothalamus.

Second, determine what happens to TRH, TSH, T3/T4, metabolic rate if
the following conditions occur (increase or decrease from baseline
levels).  Also, determine if a goiter is present or not.

Conditions:
1. No hypothalamus
2. Hyperactive hypothalamus
3. No pituitary
4. Hyperactive pituitary
5. Destroy thyroid
6. Tumor on thyroid
7. Ban iodized salt
8. Graves disease

ANSWERS FOR CONDITIONS:
1. all decrease, no goiter
2. all increase, yes goiter
3. TRH increase, others decrease, no goiter
4. TRH decrease, others increase, yes goiter
5. TRH and TSH increase, T3/T4 and metabolic rate decrease, goiter not
applicable
6. TRH and TSH decrease, T3/T4 and metabolic rate increase, no goiter
7. TRH and TSH increase, T3/T4 and metabolic rate decrease, yes goiter
8. TRH and TSH decrease, T3/T4 and metabolic rate increase, yes goiter

Problem:
What are the evolutionary advantages of each of the functions of
increased cortisol in stress?  In other words, how would these functions
been beneficial to a caveman fighting for survival against, say, a wooly
mammoth (a situation of high stress)?

1. Glucose sparing: Glucose is spared (by using fatty acids for fuel and
amino acids for tissue repair) so that in the case of starvation there
would be glucose available to the brain.
2. Bone resorption: If a bone was broken, there would be extra calcium
available in the bloodstream for repair (it takes more calcium to repair
a bone than to maintain one).
3. Sympathetic responses: This prepares them for fight or flight.
4. Red blood cell replacement: In case of bleeding, erythropoietin makes
bone marrow produce lots of red blood cells.
5. Immunosuppression/Anti-inflammatory: Allows the caveman to ignore the
body's exaggerated response to injuries and continue the fight.
6. Psychological/Analgesic: The mood elevation and pain relief would
sustain the caveman's will to live.

How are each of these functions maladaptive in modern times?

1. Glucose sparing: In the case of extreme dieting, there is muscle loss.
2. Bone resorption: This causes brittle bones (and there is not usually
a risk of broken bones in modern day stressful times).  For example,
this is a side effect of steriod treatment.
3. Sympathetic responses: Prolonged glucocortoid excess leads to high
blood pressure , particularly when there is no physical expression of
"fight or flight" to decrease blood pressure (as there often isn't when
people today are stressed out).  This is the most maladaptive function
of increased cortisol in modern times.
4. Red blood cell replacement:  Prolonged red blood cell elevation can
lead to polycythemia, in which you have more cells in the blood than needed.
5. Immunosuppression/Anti-inflammatory: This could cause people to
ignore injuries that should be treated.  Other than that, this function
is actually sometimes beneficial today.  For example, it helps in
treatment to prevent rejected organs.
6. Psychological/Analgesic:  There is a risk of addiction.

 

Cut these out, mix them up, and then have the students match them.  Each
line is a hormone signal pathway.

DA      Prolactin        Breasts
GHRH    Growth Horomone   Liver
SS      Growth Hormone    Liver
GnRH    FSH and LH        Gonads
TRH     TSH              Thyroid
CRH     ACTH             Adrenal Cortex

T/F  Hormones only have an effect on their own receptors, they cannot
effect other hormone receptors.
False

T/F Hydrophobic hormones bind to extracellular receptors
False

Why do hydrophobic hormones need protein carriers?

If they did not have a protein carrier they would stick to each other
and glob up in the bloodstream.  They also need the protein carriers
to direct them where to go.

If a hormone level is low, what happens to the expression of their
receptors?
upregulation

If a hormone level is high, what happens to the expression of their
receptors?

downregulation

Cut these out and have the students match the definition with the word

Cervical                                    neck
Thoracic                                  chest(ribs)
Lumbar                                    just below bottom rib
Sacral                                       Pelvis
Spinal cord                              gray inside, white out
brain                                       gray outside, white in
Dorsal root                             afferent
Ventral root                            efferent
somatic sensory                      things you are aware of and can control (touch, pressure, heat, cold)
special sensory                       originate outside body and need to become conscious of (vision, hearing,taste)
visceral sensory          variables that are being monitored and checked but you are not aware of (blood pressure)
PNS  afferent                         somatic sensory, special sensory, visceral sensory
PNS efferent                          somatic motor, autonomic
Autonomic                           sympathetic, parasympathetic  

Explain the steps involved in synthesis and storage of Thyroglobin, T4, and T3.

Answer: 

1.  Iodine trapping.  -Get iodine into collicular cells  -Iodine is taken in using the Na+/K+ gradient by primary active transport.

2.  Thyroglobin synthesis.  -Manufactured in the  ER

3.  Iodinate tyrosine in the thyroglobin.  -Move the thyroglobin into the colloid.

4.  T3/T4 formation and storage.  -T4 and T3 molecules attach to the hydrophilic thyroglobin protein, if they were not attached they would just diffuse out because they are hydrophobic.

5.  TSH stimulates endocytosis back into the thyroid follicle cell.

6.  Secretion of T3 and T4.  -All stimulated by TSH 

Q:  Multiple sclerosis is a common central nervous system disease in
young individuals.  It is caused by autoimmune destruction of myelin. 
Expain what myelin is and how it relates to multiple sclerosis.

A:  The axons of most neurons are covered in myelin, anywhere up to
200 layers of highly modified plasma membrane wrapped around the axon
by a nearby supporting cell.  In the brain and spinal cord the cells
forming myelin are called opigodendrocytes.  In the peripheral nervous
system, single myelin forming cells (called Schwann cells) form one
individual myelin sheath.  The myelin sheath speeds up conduction of
the electric signals along the axon and conserves energy.  With the
disruption of myelin, as seen in MS, slowing of conduction velocity
leads to failure of conduction.  After years, this can result in a
coma and early death due to respiratory failure or infection.

Classify the following hormones as most likely acting on an
extracelleular or intracellular receptor.  What is the deciding factor
in this behavior?

a.  cortisol
b.  insulin
c.  thyroxine (T4)
d.  estradiol
e.  epinephrine
f.  Follicle Stimulating Hormone (FSH)

ANSWERS:
a. intra b. extra c. intra d. intra e. extra f. extra

 

the degree of polarity (and thus water solubility) is the main factor
of where these hormones act upon.  Steroid hormones and the thyroid
hormones of amines are hydrophoic, so they are able to pass through
the membrane to the inside of the cell where they can act (a, c, d). 
Peptides and catecholamines (the other subgroup of amines) are
hydrophilic and, so they typically act on the cell membrane (b, e, f).

 Questions:

What gland is called the master gland?  A: Pituitary


 

What gland would more accurately be called the master gland? Why? A: Hypothalamus, this gland actually controls most of the endocrine system including secretion from the pituitary gland

Where does the hypothalamus receive input information? A: Peripheral receptors, cortical area, limbic system, conditions of the blood

What are the hypothalamus/posterior pituitary responsible for? A: Release of ADH, causing retention of water , and release of oxytocin, causing uteral contraction and secretion of milk

What are the hypothalamus/anterior pituitary responsible for? A: Release of hypophysiotropic hormones

Discuss the three main types of hormones covered in lecture (amines, steroid hormones, peptide hormones).  What are these hormones synthesized from?  Is each hormone hydrophilic or hydrophobic?  Does this hormone bind to cell surface receptors? Does this hormone require a carrier for transport?

ANSWERS

Amines

Synthesized from:  amino acid tyrosine

Hydrophilic:  catecholamines, epinepherine, norepinepherine

Hydrophobic:  thyroxine

Bind to: extracellular receptors

Dissolved: dissolved in plasma – don’t require a carrier protein

 Steroid Hormones

 Synthesized from:  cholesterol

Hydrophobic: insoluble in water, easily cross the lipid membrane

Bind to:  intracellular receptors

Dissolved: transport in blood, requires a plasma protein carrier for transport

 Peptide Hormones

 Synthesized from:  amino acids – joined together by peptide bonds

Hydrophilic: dissolve in water

Bind to:  exracellular receptors

Dissolved: dissolve in blood plasma, don’t require carrier

make chart and diagram starting from the trh to t3 and t4.  list the organ they come from, the organ the go to
what type they are, and if they have a function what it is.  then go through and list what the level of the
hormone would be if you hypersitimulated or hypostimulated each one. 

t4 and t3 come from the thyroid gland and t4 is the storage from of t3,  t3 makes heat, atpase pumps
adrenergic receptors and growth development.  trh releases tsh, and tsh stimulates t3 and t4. 

if you block out t3 and t4  trh, and tsh will be high, if you make them high, the hormones will be low
if you block tsh t3 and t4 will be low, and trh will be high, if you hyperstimulate it it will make t3 and t4 high
and trh low. 
if you block trh, all of them will be low, if you hypersecrete then trh will be high, tsh will be high, and t3t4 will
be high

1.) A patient of yours comes in for a sick visit and reports that she is cold all the time and has gained 10 pounds in the past 2 weeks.  Her mother is concerned because she hasn’t gotten out of bed in 2 days and seems very lethargic and fatigued.  You, being the astute doctor that you are, immediately suspect hypothyroidism.  What tests do you order that would distinguish the type of hypothyroidism that this patient may be suffering from?  What levels lead to which diagnosis?  How do you treat it?

       First, you need to distinguish between the types of hypothyroidism that may be occurring.  Appropriate tests that you would initially start with would include hormone levels for TRH, TSH, and T4. 

       Typically for hypothyroidism caused by an iodine deficiency, TRH and TSH levels will be elevated because there is no inhibition of their release by T4.  T4 will also be low because it is not being synthesized due to a lack of iodine.

       For Hashimoto’s disease, the same tests would be ordered, but would yield very different results.  Again, T4 levels will be low because there are antibodies that are attacking thyroid tissue, destroying it.  Also, TSH levels will be high due to a lack of T4 in the blood and no inhibition of release is taking place.  However, TRH levels are likely only slightly elevated or are normal because some T4 is still able to be produced and has only a small inhibitory effect on the thyroid gland.  A test for T-cell function against thyroid gland tissue would be needed to distinguish this type. 

       Treatment of iodine deficiency can be treated with the addition of iodine to the diet.  Treatment of Hashimoto’s disease would require the addition of pharmaceutical T4 to the body.

Physiology 335 Fall, 2006

Test 2 – Questions and Activities

Muscle Physiology

Endocrine System

1.      True or False.  Lipid-soluble hormones bind to a receptor protein on the receptor membrane stimulating production of a second messenger.

a.      ANSWER: False

2.      All of the following are groups of hormones except:

a.       Polypeptide

b.      Steroid

c.       Thyroxine

d.      Amino acid derived

                                                        i.      ANSWER: C

3.      Hormones that act to return the body to within acceptable limits from extreme conditions are called ___________ hormones.

a.      antagonist

1. The withdrawal reflex excites the _____A____________muscles and inhibits the ____________B_________muscles. The crossed-extensor reflex excites the ________C________muscles during excitation of the ___________________ muscles.

A:        ipsilateral flexor

B:        ipsilateral extensor

C:        contralateral extensor

D:        ipsilateral flexor

2. Symptoms of ___________A___________include sensitivity to cold, weight gain, fatigue, change in skin tone, hair, appetite, gastrointestinal and mental functions.

A: Hypothyroidism

I had the girls draw each of the endocrine pathways and then proceeded to knock out various structures and give them several scenarios from which they were to determine how the pathway would be affected, etc.

1. True or False.  The surge in FH is due to positive feedback by estrogen.
   1. ANSWER: FALSE: Surge in LH (FH is lower due to inhibin)
2. Which of the following causes the epiphyseal growth plates to fuse?
   1. Growth Hormones
   2. Estrogen
   3. Testosterone
   4. Cholesterol
   5. A, B, and C
   6. A and B
   7. B and C
   8. All of the above

                                                               i.      ANSWER:  G – the sex hormones cause the growth plates to fuse

3. Follow up question: What happens if growth hormones are not present but the epiphyseal growth plate is not yet fused
   1. ANSWER: dwarfism

The predominant hormone type secreted by the hypothalamus is:
a)amine
b)peptide
c)steroids
d)hydrophilic

answer:  peptide

1.  You have a tumor in your pituitary gland.  Which of the following
is possible?
      A) Hupersectretion of cortial releasing hormone
      B) Hyposecretion Of ACTH
      C) A decrease in cortisol secretion
      D) all of the above
     *E) none of the above

2.  Which of the following is true of a thyroid receptor?
     *a) They are located on the cellular membrane
      b) They are located inside the cell
      c) They have low sensitivity
      d) A carrier protein is needed in order for thyroid H to react
with the receptor
      e) b and d

The question was: what is the cause of a Lub Gurgle Dub Whistle and why?  The answer to this was that the first heart sound was due to the gurgle was due to an insufficient AV valve whereas the whistle was due to a stenotic AV valve.

The question for tonight was “ how does sympathetic stimulation effect different receptors?” Sympathetic stimulation of alpha-adrenergic receptors cause vasoconstriction to decrease blood flow to that location whereas sympathetic stimulation of beta-adrenergic receptors lead to vasodilation to cause an increase in blood flow to that location.

As a warm up we discussed how the body responds to a drop in blood pressure due to a hemorrhage.  A blood pressure leads to decreased firing by arterial baroreceptors, which decreases parasympathetic discharge to the heart, increases sympathetic discharge to the heart, increases sympathetic discharge to the veins, and increases sympathetic discharge to the arterioles. 

This week we worked on filling in a blank worksheet of nueromuscular
junction.  We labeled the channels and the steps of the action potential. 

This week the exercise was to put together the crossbridge and we worked
on tension vs time graphs etc.  The students helped to draw the graphs
on the board.  Similar to the questions in the study guide.

Q:  List the amines and steroid hormones.  What happens when there is a tumor on the pituitary gland?

Q:  Draw the stages of 21 day cycle of the femal reproductive system.

 

When blood glucose is low _glucagon   is released from the alpha cells of the pancreas and this process is stimulated

a)Gluconeogenesis

b) Glycogenesis

c) Protein Synth

d) Lipid Synth

Peptide Hormones and Catecholamines are _________ ao they bind to ___________ receptors and utilize a ___________like cAMP to produce a ____________  response.

lipid soluble, intercellular, second messenger, slow

Question:

I drew pictures on the board similar to pictures in the book.  The first was of how the sarcoplasmic reticulum and t-tubules wrap around the myofibril and where the plasma membrane was in relation to it. The second contained the t-tubule, plasma membrane, sarcoplasmic reticulum, DHP receptor, ryanodine receptor, and calcium channel.  I had them label the different parts in each picture, where the AP propogated, and what happened when calcium was released.  

My question was more of a step through process of the contraction of a
muscle from the start of an action potential at the neuron to the
cross bridge cycle of actin and myosin.  We drew it on the board and
had them go through it step by step and they did really well. 

My idea for a question this week went over very well.  The group played pictionary using the four tension diagrams in the notes.  One member of the group would draw a diagram and the others would guess which diagram, then the drawer would explain the diagram.  It seemed to work well because they had to draw the diagrams based on memory, since we hadn't looked at them yet during the session.  Everyone seemed to feel that it was a good review and helped them better understand what the diagrams showed.

This week I quizzed the group on the three types of hormones.  The group had to tell the three types, what makes each type, common hormones for each, and which are hydrophilic and which hydrophobic.  Everyone seems to enjoy being quizzed and trying to remember things without looking.  Although it's hard it gives the individuals a better idea of what the actually know.

My question 4:

Single smooth unit muscle cells can stimulate each other because they have

1. a pacemaker
2. diffuse junctions
3. gap junctions
4. tight junctions
5. calcium pumps

Question 5:

An ECG would be useful for determining a patient’s:

1. heart murmur
2. stroke volume
3. caridiac output
4. blockage of conduction of electrical signals between the atria and the ventricles
5. none of the above

answer d

Question of the Day:  Rigor Mortis is a stiffening of the skeletal muscles approximately 12 hours after
death. This is a result of…
a) The lack of movement and therefore absence of neural signals from the Nervous System regulating cross bridge cycling.
b) The contractile proteins, Actin and Myosin, become very rigid and inflexible post-mortem, and therefore inhibit any
movement
c) The decline in [ATP] in cells inhibit the breakage of the Actin Myosin link, and therefore, the thick and thin filament
cannot be pulled past each other. 
d) If you don’t need to move, why would your muscle fibers need to move?

Preparing for a question – send an e-mail like this one:

I want you to show me how an action potential is propagated to the axon terminal, how is stimulates NT release into the synapse (explaining all the roles of Na+ and Ca2+ and Ach and also the implications of chemicals such as TTX and botulism toxin) and show the resulting action potential (if t here is enough depolarization of the membrane) in the muscle cell. At the muscle fiber, you should know the physiology and anatomy of the T-tubules, the lateral sacs, the ryanodine receptors, the role of Ca2+ and its receptors, and where all these reside in relation to the sarcomere (thick, thin filament, z line, ect...) Finally, also know EACH STEP in the cross bridge cycling pattern chemically ([ATP], [ADP], and [Pi] molecules) physically (how the power stroke occurs) and graphically in the hyperbolic force-velocity and force tension curves. *Know each step in the cycle chemically, physically and graphically and know why and how they relate to each other!!!!! HINT * please know the difference in the latent period of an isometric twitch graphically and be able to explain why this occurs. Also make sure you understand tetanus and
fused tetanus and what that looks like graphically..

Question of the day: What is the role of the
corpus leuteum and what happens to it after ovulation _______, end of menstrual cycle given no fertilization______, and end of
cycle given that there is fertilization_________.
*It becomes the “yellow body” secreting E + P, but predominantly P.
* It begins to degrade; consequently it secretes less and less E+P until the concentrations of these HM’s fall below the threshold
and trigger menstruation.
*It does not degrade, but keeps secreting substantial amounts of P to keep an in-utero environment, conducive for the
developing fetus. Later it is supersede by the placenta and its purpose becomes obsolete.

Question:

Which of the following parts of the sarcomeres under go a change in
width during the shortening of muscle?

a) I band
b) Z line
c) A band
d) H zone
e) Both a) and d)

Answer: e) Both a) and d)


 

Had the students go to the white erase board to compile a list of the
properties of hormones (peptides/proteins,amines,steroids) such as are
they hydrophobic or hydrophilic and what are the characteristic of
these two different types within the body.


 

Leader Questions PLT 2007

Test 3--Cardiovascular

1.)    A guy that had way too much to drink at the Badger game this weekend decides to drive home and on the way home he hits a deer.  The deer flies through the windshield, severing the nerves connecting his baroreceptors with the brainstem.  Answer the following questions.

a.       The nerve connecting the baroreceptors with the cardio-inhibitory portion of the brainstem was severed.  What will result from this?

The heart will likely beat at least 100 beats per minute no matter what because there will be no parasympathetic innervation going to the heart.

b.      The nerve connecting the baroreceptors with the cardio-acceleratory portion of the brainstem was severed.  What will result from this?

If this connection is severed, a decrease in MABP will not lead to an increase in heart rate or stroke volume.  The lack of blood to the brain will likely cause the person to pass out allowing the body’s metabolism to return to normal.

2.)    Which is more influential, body wide effects or local effects, in determining MABP?  Why is this the case?

Body wide effects always trump local effects because the brain’s needs come before all other organ’s needs when determining allocation of the blood.  The brain is vital in regulating all other processes and requires constant blood flow at all times.

3.)    Diuretics are used to treat excessive fluid accumulation due to heart failure.  What other ailment might they be able to treat as well?

Diuretics could also be used to treat high blood pressure.  Because they cause the secretion of sodium and water, the total volume of fluid would go down in the body.  Likewise, blood volume would also decrease and mean arterial blood pressure would also be reduced.

You notice a proud blue vein in your lazy skinny brother's temple as he
berates you about not picking him up from his friend's house as you had
offered (he was late). You know it is probably related to hormonal
vasoconstrictors, but because he just jogged the mile home, you know the
exertion also contributes venous pressure, via what other return
mechanisms? (skeletal muscle pump, respiratory pump).

Look at ventricular action potential curve in the text(Figure 12-14 b,
p.400). Why doesn't the P wave activity appear anywhere? (P wave shows
atrial depolarization.) Which valves could be open during the P wave? (AV
valves)

Match the area affected with the effects of sympathetic nerves on the heart
1. Ventricular muscle              A. Increased conduction rate
2. AV node                         B. Increased heart rate
3. Atrial muscle                   C. Increased contractility
4. SA node                        
 
Answer 1)C 2)A 3)C 4)B

Match the area affected with the effects of parasympathetic nerves on
the heart
1. Ventricular muscle              A. Decreased contractility
2. AV node                         B. No significant effect
3. Atrial muscle                   C. Decreased conduction rate
4. SA node                         D. Decreased heart rate

Answer 1)B 2)C 3)A 4)D

Problem:
What is the main difference between skeletal muscle action potentials
and cardiac action potentials? Why is this difference important for
proper cardiac function?

 Answer: Cardiac action potentials involve L-type calcium channels which
stay open for a long time.  This causes a plateau phase in the action
potential in which L-type calcium influx is balanced by potassium
efflux, keeping the membrane depolarization constant.  This plateau
phase is responsible for the long refractory period of the cardiac
action potential.  The long refractory period prevents summation of
heart beats and also ensures complete ventricular filling, which can
only occur when the ventricular muscle is relaxed.

Q:  What are two basic functions served by the arteries, and what
characteristics in structure aid them in serving these functions?

A:  1. The arteries serve as low resistance tubes for conducting blood
to various organs to give them life-sustaining oxygen, etc.  To this
effect, they have a large radius.
    2. The arteries serve as "pressure reservoirs" for maintaining
blood flow through the tissues during diastole.  To this effect, they
have a high elasticity.

 

Question:

What is the hematocrit?  What other components make up blood?  What
component (cell fragment) of blood determines clotting potential the
most?

The hematocrit is a rapid assessment of blood composition.  It is the
percent of the blood that is composed of erythrocytes (RBCs).  The
other components that make up blood are the plasma, which includes
water, ions, proteins, nutrients, hormones, wastes, etc. and the buffy
coat, which is mostly white blood cells.  Platelets are the cell
fragment that most determine clotting potential.    
    

Q: Stimulation of the L-type CA 2+ channels will directly_____________?
A: increase the strength of ventricular contraction

Q: what component of blood vessel walls is present in all types of blood
vessels?
A: endothelium

Q: During which phase of the cardiac cycle is the semi lunar valve open?
A: ejection or systolic

Question:

All five cardiac cell types have_________ channels and ________ channels.
Only cells with pacemaker activity have ________channels and
_________channels.
_____channels allow fast conduction velocities in ________, _________,
and ________ cell types. 

answers: L-type Ca, K+, Naf, Ca(t), Na+, muscle, conducting, inter nodal

Draw Figure 12-23, which shows a normal pacemaker potential, a pacemaker potential under sympathetic stimulation, and a pacemaker potential during parasympathetic innervation.

Then, make them decide how the permeability of the ion channels change to create the different profiles of the pacemaker potential.

Answers:

Under sympathetic innervation:  The heart rate is increased.  (Permeability = P). 

P potassium decreases, P funny sodium channels increases, P T-type calcium channels increases

Under parasympathetic innervation:

P potassium increases, P funny sodium channels decreases, P T-type calcium channels decreases

Then ask the group:

Fast action potentials are generated by what ion channels?

Answer: Fast sodium channels (muscle and conducting cells)

Slow action potentials are generated by what ion channels?

Answer: L-type calcium channels (nodal cells)

Problem:

       Cut out the following words:

Flow rate

Pressure Gradient

Resistance

Vessel Length

Viscosity

Radius^4

Cardiac Output

Mean Arterial Pressure

Total Peripheral Resistance

Then, cut out some mathematic signs (+, =, x)

Have them put together the important equations of the cardiovascular system

Specifically, Flow = Pressure Gradient/Resistance or Presure = Flow x Resistance

Then, Resistance = Vessel Length x Viscosity (8)/Radius^4

Then, on the board, put numbers into the equations, so the group can see what happens to the flow rate when the resistance increases, or what happens to the resistance if the radius increases.  This will help the study group understand these eqautions, and the relationships between the variables.

why is it important that the phase 4 in muscle cells is flat, but for the conducting cells it is not and drifts. 
because you want fast conduction and you want a baseline so that you can easily get cell activity, where on the
muscle you want it to contract and then remain still ready for the next excitation

1.)    How would sympathetic stimulation affect each of the types of membrane channels found in the sino-atrial node?

Sympathetic stimulation would increase the permeability to funny Na+ channels, T-type Ca channels, and decrease the permeability to K+ channels.  This is the case because funny type channels control phase 4 increasing its slope and the T-type Ca channels increase the slope of the upstroke.

2.)    How do both the sympathetic and parasympathetic nervous systems affect heart rate and stroke volume?

The sympathetic nervous system increases stroke volume and heart rate.  The parasympathetic nervous system decreases only heart rate and does not affect stroke volume.

3.)    How do Beta-blocker drugs work to decrease blood pressure?  Include all systemic effects in your answer.

Beta-blockers block beta adrenergic receptors.  This would have the function of preventing the heart rate and stroke volume from increasing, preventing any increase in cardiac output.  This would also cause vasodilation in the vasculature.  These effects combined would cause a decrease in blood pressure.

1.)    Describe the path an action potential will take starting at the SA node.  What particular feature of this pathway accounts for the lag between atrial and ventricular contraction.

An action potential starts at the SA node and travels from cell to cell via gap junctions to the AV node.  It is here where the lag occurs due to slower conduction in the AV node.  Depolarization of this node then enters the interventricular septum wall and travels down this wall via the bundle of His.  The bundle of His then divides into the right and left branches and eventually makes contact with the Purkinje fibers.  The Purkinje fibers then rapidly distribute the electrical signal throughout the cell.

2.)    If a patient has a defective AV valve and you’re listening to their heart, what will you hear and why? (gurgle = valve insufficiency, whistle = valve stenosis)

The sound you hear is lup – gurgle – dup – whistle.  You hear the gurgle after the lup because the AV valve is supposed to be closed at this point but is leaking, the definition of a valve insufficiency.  This whistle follows the dup, or ventricular contraction, because the valve fails to open entirely causing fluid to be squeezed through a small opening.

3.)    Why does the pressure in the aorta rise immediately after the bicuspid valve closes?

Due to the size of the aorta, the movement of blood in the body, and the histology of the aorta (made up of smooth muscle and elastic tissue mainly), the increased volume in the aorta causes it to stretch beyond its capacity.  Because of this expansion and the intrinsic property of smooth muscle to contract when it is stretched, the aorta pushes back on the fluid, increasing the pressure immediately after the bicuspid valve closes.

i had them lay out the cataolitic and metabolic pathway, in a straight way and where it occurs.  And then point
out in which process would they need glucagon which one insulin. 


why is the av valve called that? (antrioventricular) because it lies between the atrium and the ventricle. 

 How do you remember which side of the heart has the tricuspid valve.  ( the heart lies on the left size and therefore
takes up a lobe of lung, therefore only two.) so on the right you have three lobes.  therefore the right side of the
heart has three lobes.

 

Q:  In an EKG, what causes a. the P wave? b. the T wave? c. the QRS
complex? d. What determines the delay between the P wave and the Q
wave?

A.  a. atrial depolarization
    b. septal wall/ventricular depolarization
    c. ventricular repolarization
    d. the AV node -  it slows down conduction


 

Problem:
If a doctor were listening to a patient's heartbeat and heard the
following sounds, what would be the diagnosis in each case?
A)  "lub whistle dup"
   (Answer: stenotic semilunar valve)
B)  "lub gurgle dup"
   (Answer: insufficient AV valve)
C)  "lub dup gurgle"
   (Answer: insufficient semilunar valve)
D)  "lub dup whistle"
   (Answer: stenotic AV valve)

QUESTION:
1. What happens to the following areas (in the short term) when MABP
is decreased?
Baroreceptors - decrease
VM - increase
CA - increase
CI - decrease
Heart Rate - increase
Ventricle force - increase
Stroke Volume - increase
Vein/arteriole diameter - decrease (constrict)

**Opposite effects occur with increase in MABP**

2. Organize the following info into a flow chart with arrows:
-Baroreceptors = sense stretch, mechanical receptors; inhibit VM and
CA which are sympathetic systems; stimulate CI which is
parasympathetic system
-VM = affects veins and arterioles; constricts them using alpha 1
receptors that accept norepinephrine; arterioles can dialate when beta
2 receptors accept epinephrine or GC
-CA = affects SA node and ventricles/contracting tissue; using beta 1
receptors that accept epinephrine increase heart rate; using beta 1
receptors that accept epinephrine increase force in contracting tissue
to increase stroke volume and cardiac output
-CI = affects SA node; uses acetylcholine on muscarinic receptors to
decrease heart rate

Q:  Complete the following chart comparing ion channels and various cell types:

Specifically, which channel(s) are responsible for the following properties:

1)      rapid depolarization of conducting cells and myocardial pumping cells

2)      slow depolarization of autorhythmic cells

3)      pacemaker potential of autorhythmic cells

4)      long refractory period

A:

1)      Fast Na⁺

2)      L-type Ca²⁺

3)      K⁺, I_f(Na⁺), and T-type Ca ²⁺

4)      L-type Ca²⁺

Question:  What is one major benefit to decreased velocity of flow
within the capilaries?

Answer:  More time for diffusion.

QUESTION:
1. Draw skeleton of Wiggers Diagram - one wide section, one skinny
section, one wide section, one skinny section.  Have students label
and draw in the following:

-Sections A, B, C, D = ventricular filling, isovolumetric contraction,
ejection, isovolumetric relaxation
-EDV and ESV
-Volumes = aortic flow and ventricular volume
-Pressures = aortic, ventricular, atrial
-Heart sounds = lub, dub
-ECG = P, Q, R, S, T
-Valves open or closed = atrioventricular and semilunar
-Atrial kick

**Make sure students can explain why pressures increase and decrease
and why certain pressures must overcome others in order to move blood.
**All parts of the diagram should be explained by the student that
draws them in.

2. Draw action potential graphs for nodal, conducting, and cardiac
force generating muscle.  Have students label the phases for each
one.  Then, have them sketch on the same axes what happens with
sympathetic and parasympathetic innervation.

-Nodal = phase 4, 0, 2, 3
-Conducting = phase 4, 0, 1, 2, 3
-Cardiac force generating = phase 4, 0, 1, 2, 3

With sympathetic innervation = faster conduction velocity, faster
upstroke, plateau lasts shorter amount of time, increased frequency of
action potentials

With parasympathetic innervation = slower conduction velocity, slower
upstroke, plateau lasts longer amount of time, decrease frequency of
action potential

QUESTION:
1. Trace the path of blood.  Draw diagram including the following:
(label with numbers then have students come up to the board to
identify and label the structures) R and L atria, R and L ventricles,
inferior and superior vena cava, aorta, pulmonary artery, pulmonary
vein, tricuspid AV valve, pulmonary semilunar valve, aortic semilunar
valve, bicuspid AV valve

Here's the path of blood the students should be able to describe and
discuss: start with blood as it's leaving the capillary bed of a
skeletal muscle, moves through venules and veins to enter vena cava,
dumps into R atrium, increase pressure in R atrium to overcome
pressure in R ventricle, then tricuspid AV valve opens and blood moves
to R ventricle, again a pressure increase to enter pulmonary artery by
flowing through pulmonary semilunar valve, travel to lungs to exchange
gases, use pulmonary vein to enter L atrium, increase pressure in L
atrium to overcome that of L ventricle, blood flows through bicuspid
AV valve into L ventricle, increase pressure in L ventricle to
overcome that of aorta, blood passes through aortic semilunar valve,
expansion of aorta as blood passes through, move through arteries,
arterioles, and capillaries to enter the skeletal muscle tissue (in
this example)

2. Which ventricle has more muscle mass?

Left because it pumps to systemic circulation versus pulmonary circulation of Right side.

Question:  True or False

Baroreceptors sensing an increase in MABP will cause decreased firing to
the brain causing less stimulation of the sympathetic control centers in
the brain.

Hemorrhaging will lead to a response aimed at increasing MABP.

During exercise, TPR will decrease.

Answers:
F,T,T

Which channel(s) could you inhibit or stimulate to:
a) slow HR
b)increase strength of ventricular contraction
c) slow conduction thru AV node

Answer:
a) since HR det by pacemaker potential, could decrease PNa(f) or
decrease PCa(L)
b) increase PCa(L)
c) decrease PCa(L)e deficiency and grave's disease can both cause goiters.  What are the levels of T3 and T4, TRH and TSH in each case, and why? 

Question:  A doctor hears Lub whistle Dub in his/her stethoscope.  How
will this change what the Wigger's diagram looks like?

Answer:  This means that the semi Lunar valve is having difficulty
opening.  As the ventricle contracts it will have to push harder to
expel all the blood which will increase the pressure in the ventricle.
This means that there will be a larger peak of ventricular pressure in
the Wigger's diagram.

If an individual had a defective SA node and their blood pressure
were to decrease what relative change to the heart rate would occur?
    The baroreceptors would fire less removing the inhibition of the
VM and CA which activate the sympathetic nervous system.  However,
because the SA node doesn't work the AV node would now represent the
pacemaker.  This means that the heart rate would increase but not to
the same level as if the SA node was functioning.

What are the conditions when autotransfusion occurs, and what are the mechanisms?

Autotransfusion is the movement of interstitial fluid into the vascular system.  It is caused by low blood pressure and low Pc.  The short term compensation is a decrease in Na excretion and retain water.  Ultimately, the patient will need to drink lots of fluids or recieve fluids via IV. 

Ques:  List the following in the order in which the blood would flow if it were leaving the left ventricle first?

venules
right ventricle
pulmonary vein
arterioles
aorta
lungs
pulmonary artery
left atrium
capillaries
veins
right atrium

Answer:
1. aorta
2. arterioles
3. capillaries
4. venules
5. veins
6. R atrium
7. R ventricle
8. pulmonary arteries
9. lungs
10. pulmonary vein
11. L atrium

 Question: What do the Peripheral chemoreceptors sense? What do the
central chemoreceptors sense? What is the Hering-Breuer reflex?

Peripheral chemoreceptors sense a decrease in O2, and a decrease in pH
and weakly an increase in CO2. When PO2 drops below 60mmhg on the
dissociation curve ventilation is increased.

Cental chemoreceptors sense a decrease in pH (increase in [H+]) in brain
generated from CO2 crossing the blood brain barrier. Responsible for min
to min ventilation.

Hering-Breuer reflex is a pulmonary stretch in the luns that inhibits
medullary inspiratory neurons.

Question: Match the following ex Question

Regarding the ECG wave: 

What causes the P-wave?
What causes the QRS complex?
What causes the T-wave?
What determines the delay between the P and Q waves? 

Answer:
Atria contraction, Ventricle contraction, Ventricle repolarization, AV node conduction.  planations with the correct terms:

Terms:
Compliance
Elasticity
High Compliance
Low Compliance
High Elasticity
Low Elasticity

Explanations:
a.  amount a substance can stretch
b.  easy exhale
c.  unhealthey lungs
d.  amount a substance can recoil
e.  difficult inhale
f.   easy inhale
g.  difficult exhale
h.  healthy lungs
i.   associated with inhale
j.   associated with exhale

Answers: 

Compliance a, i
Elasticity d, j
High compliance f, h
Low compliance e, c
High elasticity b, h
Low elasticity g, c

Question:

List the following stimlants in the correct spot on the blank chart. 

sympathetic nerves
Epinephrine
Eicosanoids
Internal Blood Pressure
Brakykinin
Substances released during injury
Osmolarity
K+, CO2, H+
Atrial natriuretic peptide
Vasopressin
Osmolarity
Nitric Oxide (neurons releasing) 
Angiotensin II
Decreased Oxygen
Adenosine
Endothelin-1

Question: You venture off to a different planet. There you find the
atmospheric pressure to be 540mmHg. The composition of the air is 43%
N2, 32% O2, and 35%CO2. Calculate the partial pressures for each gas.

N2  540 x .43 = 232.2 mmHg
O2 540 x .32 = 172.8 mmHg
CO2 540 x .25 = 135mmHg

Question:
 
As the diameter in the alveoli ____________, pressure __________.
Alveolar type ____ cells secrete __________. Surfactant is a mixture
composed of _________ and ____________. It helps to lower __________
____________ of the water layer at the alveolar surface, which increases
lung __________. A ___________ breath __________ its secretion by
stretching type _______ cells. Its concentration _____________ when
breaths are ________________.


 

Answer:

As the diameter in the alveoli decreases, pressure increases. Alveolar
type II cells secrete surfactant. Surfactant is a mixture composed of
phospholipids and protein. It helps to lower surface tension of the
water layer at the alveolar surface, which increases lung compliance. A
deep breath increases its secretion by stretching type II cells. Its
concentration decreases when breaths are small. From table 13-4 on page
105 of lecture notes.

Question

What is the small spike seen in the internodal conductors and bundle of
his/purkinjie membrane potential graphs?

Answer

This spike indicates that fast Na channels are presents and cause a rush
in of positive ions.

Question

How does the body increase and ensure blood flow to the heart?

Answer

Skeletal muscles contract, decreasing the diameter of the veins, pumping
the blood towards the heart.  Also, values ensure that the blood will
not flow the wrong direction away from the heart.

Problem and solution. Cardiac physiology. Rehearse drawing the
membrane potential & permeabilities curves as given in Figures 12-12
and 12-13. Relate the contribution of each ion's flow to the
polarization/depolarization of muscle and nodal cells. Critique
another's presentation.

 Question: Which of the following could lead to an increase in tissue
fluid volume? (aka edema)
          a.) decreased concentration of proteins in the ISF
          b.) increased hydrostatic pressure in the ISF
          c.) decreased concentration of plasma proteins
          d.) decreased hydrostatic pressure in the capillary


Answer: c.) decreased concentration of plasma proteins

Q: What channels are stimulated by parasympathetic nerve action
potentials coming to the heart?

A: Increase in Potassium channels, decrease in "funny" Sodium channels,
and a decrease in Ca T-type channels.Parasympathetic activity decreases
rate of diastolic depolarization.

Q: What channels are affected by sympathetic nerve action potentials
coming to the heart?

A: Decrease Potassium channels, increase "funny" Na channels, increase
in Ca T-type. Sympathetic activity increases the rate of diastolic
depolarization.

Problem: Why do people who are having an allergic reaction take
epinephrine, and why does it cause vasoconstriction instead of
vasodialation from the last section?

Question:
draw axes of a graph and have students tell you how to fill it in to
create the oxy-hemoglobin curve. then ask them what happens when it is
shifted to left/right and what causes the shift.

Answer:
HB saturation goes on the y-axis (0-100%) and PO2 goes on the x-axis (0-
100+ mmHg). steep portion of the graph below PO2 60 mmHg, plateau above
60 mmHg. physiologically relevant b/c tissues have PO2 of 40 (on steep
part), so it is relatively easy for them to unload O2. the lungs have
PO2 of 100, so it is easy for them to hold onto O2; and the PO2 can
drop significantly with out the Hb-satuation changing significantly.
when the curve is right shifted it is easier to unload O2--> happens
with increased temp, decreased pH, increased DPG.
when the curve is left shifted it is harder to unload O2--> happens
with decreased temp, increased pH, decreased DPG 

question:
Concerning the 4 factors contributing to bulk flow...
a)which factor causes edema during starvation?
b)which factor caused edema during right ventricular failure?

answer:
a)during starvation there is a decrease in [plasma protein]
b)during right ventricular failure there would be a backup of blood in
the systemic circuit causing an increased capillary hydrostatic
pressure in systemic capillaries

Physiology 335 2005

Test 4

Respiratory

Renal

GI

Question?
Where is intrapleural Pressure found? How does it work to prevent
recoiling of chest wall and alveoli?

Answer:
The intrapleural pressure is found in the intrapleural fluid between the
alveoli/lungs and chest wall.  The alveoli was to collapse and the chest
wall would like to expand further out and so the negative pressure
prevents either from occurring.

1. If an individual with a spinal cord injury at T6, the ability to:

A. inspire is normal

B. forcefully expire is lost

C. increase inspiratory effort is normal

D. passively expire at rest is normal

E. cough is normal

2. Which of the folllowing inspiratory conditions is least likely to require medical treatmnt?

A. apnea

B. dyspnea

C. eupnea

D. hypoxia

E. hypercapnia

3. Which of the following increases the binding affinity of hemoglobin for oxygen?

A. an increase in carbon monoxide

B. an increase in carbon dioxide

C. an increase in H+ concentration

D. an increase in temperature

4. Which of the following would result in an increase in the rate of diffusion of oxygen from alveloi to the pulmonary capillaries?

A. an increase in the partial pressure of carbon dioxide in the alveoli

B. an increase in the surface area available for diffusion

C. an increase in the thickness of alveolar walls

D. an increase in the partila pressures of oxygen in the pulmonary capillaries

E. a decrease in oxygen utilization by the systemic tissues

Answers: 1. D, 2. C, 3. A, 4. B

What is an advantage to the diffusion of oxygen from the alveoli to the capillaries being achieved in the first third of the capillary bed under resting conditions?

During activities with increased blood flow, you are still able to recieve optimal oxygen levels in the blood.  Also, in environments of low oxygen (ie. high altitude) you will also be able to recieve optimal oxygen.

Q:  What are the three forms of CO2 transport in the body and what are
their magnitudes?

A:  1)Dissolved - 10%
    2)Hemoglobin Binding - 30%
    3)Bicarbonate - 60%

Q:  During mild exercise, which of the following changes? a. minute
ventilation b. arterial PO2 c. arterial [H+] d. arterial pCO2
A:  a


Q:  List factors that could contribute to the increased MV with
increased exercise.
A:  -reflex input from mechanoreceptors in muscles and joints
    -increased body temperature
    -inputs to respiratory neurons via branches from axons descending
from brain to motor neurons supplying exercising muscles
    -increase in plasma [Epi]
    -increase in plasma [K+]
    -conditioned response
    -psychological - intention to exercise

Put the following steps in order and name the process.

Process 1

A. Arteriolar dilation in organ
B. Increased metabolic activity of organ
C. Decreased O2, Increase metablites in organ, interstitial fluid
D. Increased blood flow to organ

Answer:  Active Hyperemia B, C, A, D

Process 2

A. Decreased O2, Increased metabolites, Decreased vessel-wall, stretch
in organ
B. Decreased Blood flow to organ
C. Restoration of blood flow toward normal in organ
D. Arterial dilation in organ
E. Decreased Arterial pressure in organ

Answer: Flow autoregulation E, B, A, D, C

 

Question:
T/F Quiz!
1. The O2 bound to hemoglobin contributes to the P02 of plasma
2. Hyperventilation results in an increase in the pH of systemic
arterial blood
3. The partial pressure of O2 in the systemic venous blood influences
the O2 content of systemic arterial blood
4. CO has a stronger affinity than O2 for binding Hb, therefore causing
CO poisoning
5. Anemia results in decreased Hb, which causes an increase in the
normal partial pressure of O2
6. Anemia results in an increase in the amount of O2 carried.
7. 1.5% of O2 is dissolved in plasma
8. Most CO2 is transported as bicarbonate
9. Hyperventilation causes an decrease in CO2 and subsequent
resperiatory acidosis
10. Surfactant reduces surface tension by equalizing surface tension
across different radii of different alveoli

Answers
1)F 2)T 3)F 4)T 5)F 6)F 7)T 8)T 9)F 10)T

QUESTIONS:
1. Draw a graph and label the following volumes and capacities:
-Total lung capacity
-Inspiratory reserve volume
-Expiratory reserve volume
-Vital capacity
-Residual volume
-Functional reserve volume
-Tidal volume

What is the difference between a volume and a capacity?

2. Draw the hemoglobin and PO2 curve.  Label important PO2 values,
such as 40, 60 and 100.  Label important saturation %'s, such as 75,
90, and 98.
-Explain how the curve is sigmoidal.
-What happens when factors such as temperature, hydrogen ion
concentration, and DPG concentration are increased and decreased?
-What does the mean in terms of hemoglobin's affinity towards oxygen?

3. You can have students verbally explain the following concepts:
-Anatomical dead space vs. alveolar dead space
-How surfactant works
-Steps of normal, quiet breathing
**These are useful discussion starting concepts.**

QUESTIONS:

1. Distinguish between the four different compensatory mechanisms when
talking about acid/base. 
Answer:
-Respiratory acidosis: results from abnormal CO2 retention
-Respiratory alkalosis: results from abnormal CO2 loss
-Metabolic acidosis: characterized by a decrease in HCO3-, all types
of acidosis other than those caused by excess CO2 in body fluids
-Metabolic alkalosis: reduction in plasma H+, characterized by
increase in HCO3-

2. Explain the resting position of the lung and chest wall.
Answer: Chest wall bellows out in resting position if not attached to
pleural sac.  Lung would recoil/cave in without attachment to pleural
sac.  Intrapleural pressure is negative because it holds lungs open in
resting position.  Transpulmonary pressure = alveolar pressure -
intrapleural pressure

3. State where the following molecules are secreted and/or
reabsorbed.  You can draw up a nephron and indicate the exact location
if this helps.
-Na = reabsorbed in proximal, thick ascending limb, distal with
aldosterone, collecting duct with aldosterone
-K = reabsorbed in proximal and thick ascending limb; secreted in
distal with aldosterone and collecting ductwith aldosterone
-H2O = reabsorbed in proximal, descending limb, distal with ADH, and
collecting duct with ADH
-H+, glucose, amino acids = reabsorbed in proximal
-waste = never reabsorbed, secreted in proximal

QUESTIONS:
1. Draw a graph and label the following volumes and capacities:
-Total lung capacity
-Inspiratory reserve volume
-Expiratory reserve volume
-Vital capacity
-Residual volume
-Functional reserve volume
-Tidal volume

What is the difference between a volume and a capacity?

2. Draw the hemoglobin and PO2 curve.  Label important PO2 values,
such as 40, 60 and 100.  Label important saturation %'s, such as 75,
90, and 98.
-Explain how the curve is sigmoidal.
-What happens when factors such as temperature, hydrogen ion
concentration, and DPG concentration are increased and decreased?
-What does the mean in terms of hemoglobin's affinity towards oxygen?

3. You can have students verbally explain the following concepts:
-Anatomical dead space vs. alveolar dead space
-How surfactant works
-Steps of normal, quiet breathing
**These are useful discussion starting concepts.**

1.)    Put the following respiratory structures in the order air would pass during an exspiration.

-larynx, trachea, alveolar sac, terminal bronchiole, mouth, bronchiole, pharynx, respiratory bronchiole, alveolar duct, bronchi

- alveolar sacs, alveolar ducts, respiratory bronchioles, terminal bronchioles, bronchioles, bronchi, trachea, larynx, pharynx, mouth

2.)    Why do babies that are more than 3 months premature spend their first weeks on a positive pressure ventilator and have to breath additional oxygen for the next 3 months?  (Hint: Yawn…)

- Babies born about 3 months premature have not developed the ability to produce surfactant yet.  Therefore, their lungs cannot inflate and they have trouble breathing.  They breathe additional oxygen for the next three months because they have a much more difficult time maintaining blood oxygen levels near normal because their lungs are much more difficult to inflate.

1a.  In a given blood vessel that has constant l and n so that l*n= 4, what is the radius of the vessel if the resistance is equal to 15?

R=8ln/πr⁴

15= 8(4)/ πr⁴

Answer: r = .907

1b.  If you then reduce the length of the vessel by ¼ and triple n, what is the new radius if resistance is still 15?

15= 8(4)(1/4)(3)/ πr⁴

Answer: r = .845

1c. In a new vessel if you were to shrink the radius to ⅓ its previous size what factor would the resistance change by and in what direction? 

R=8ln/πr⁴

R=8ln/π(1/3)⁴

r= (1/3)⁴ = 1/81

Answer:  it would increase by a factor of 81 (resistance would be 81 times greater). 

Question:  What factors determine how well alevolar ventilation and
pulmonary capillary perfusion are matcher? 

Answer: gravity, chemical factors, disease

Fill in the blanks with stimulate or inhibit

a. Action potentials from baroreceptors __________ the CI center
b. Action potentials from baroreceptors __________ the CA center
c. Action potentials from baroreceptors __________ the VM center
d. Action potentials from CI center__________ the SA node
e. Action potentials from CA center__________ ventricular muscle
f. Action potentials from VM center__________ the arterioles
g. Action potentials from VM center__________ the veins

Answers: stimulate, inhib, inhib, inhib, stim, stim, stim

Question:
What is the difference in central chemoreceptors versus peripheral
chemoreceptors?

Answer:
Central chemoreceptors are located in the brain and they monitor changes
of hydrogen concentrations in the extracellular fluid.  Peripheral
chemoreceptors (carotid bodies and aortic bodies) are located on the
aorta and arterioles and they sense the PO2, PCO2, and hydrogen
concentrations in the blood.  Both chemoreceptors and central receptors
are checking the blood's PCO2.

Question:  Your friend gets light headed and passes out due to lack of
oxygen.  You remember that right before he passed out he wasn't
breathing any differently than normal.  What are two possible causes for
this and why would his breathing not increase?

Answer:  Your friend could either be suffering from anemia or carbon
monoxide poisoning, in which case you may be too.  The reason his
breathing didn't increase is because the centers regulating breathing
sense p02 to determine the amount of oxygen in the blood.  In the case
of anemia and CO poisoning, the total amount of bound oxygen is greatly
reduced, but p02 isn't affected so the breathing won't increase to
combat the lack of oxygen.

Question:  If the phrenic nerve was destroyed what would be the effect
on respiration?

 

Answer:  The phrenic nerve is a part of the DRG which is in charge of
regulating inspiration.  Specifically, the DRG synapses onto the
phrenic nerve which, through alpha motor neurons, controls the
contraction of the diaphragm.  If the nerve was destroyed the
diaphragm would not contract and only the external intercostal muscles
would be available to control inspiration.

Question:

What happens to diffusion rate if you...
1. increase C
2. increase A
3. increase S
4. increase X
5. decrease C
6. decrease A
7. decrease S
8. decrease X
9. decrease MW
10. increase MW
11. double C and quadruple X
12. double A, double S, and quadruple MW
13. double C, double A, double S, triple MW
14. Double X, triple A, and double MW
15. Quadruple MW, Quadruple C, Quadruple S

Answers
1. Increase Q
2. Incrase Q
3. Increase Q
4. Decrease Q
5. Decrease Q
6. Decrease Q
7. Decrease Q
8. Increase Q
9. Increase Q
10. Decrease Q
11. 0.5 Q (decrease Q)
12. No change in Q
13. 2 Q (increase Q)
14. 0.75 Q (Decrease Q)
15. 4 Q (increase Q)

Problem: What do clearance values mean in relation to GFR?  What do they
reveal about how a particular substance is handled by the kidney?

Answer: If a substance's clearance value is equal to the GFR, it
indicates that it is being neither secreted or reabsorbed.  If its
clearance value is below the GFR, it is most likely being reabsorbed.
If the clearance value is above the GFR, the substance is most likely
being secreted.

Question:
The kidneys filter the _________, which for the most part communicated
freely with the ___________.  The two substances that do not move freely
between these two compartments are_________ and __________.

plasma, ISF, proteins, blood cells

Question:
An increase in the MABP will cause what to happen in the kidneys?
a) A decrease in GFR
b) A decrease in Na excretion
c) A decrease in renin secretion
d) A increase in aldosterone secretion

Answer:C

A decrease in MABP will cause what to happen in the kidneys?
A) An increase in GFR
B) An increase in urine volume
C) A decrease in Na re absorption
D) An increase in sympathetic activity

Answer:D

By what two hormonal mechanisms is Na reabsorption regulated?

Answer: Aldosterone and ANP

Urine excreted equals what?

Answer: (filtered + secreted) – reabsorbed

What is the difference between filtration, secretion, and reabsorption?  Draw each process in cartoon form (like in the book), and give examples of molecules that are filtered, secreted, or reabsorbed.

Glomerular filtration: not selective, 20% of plasma filtered this way, proteins, blood cells, and substances bound to proteins are not filtered the glomeralur capillaries into Bowman's Space, movement of substance from .  Example of filtered substance: urea, PAH, glucose, etc.

Secretion: selective, happend via transport proteins, 2nd route for substances to enter the the nephron, movement of substance from the peritubular capillary to the tubules (the other 80% of the plasma that was not filtered).  Example of secreted substance: Urea, sodium, etc.

Reabsorption: 178.5 L/day reabsorbed, happens to substances that your body needs, movement of substance from the tubules to the peritubular capillaries.  Example of reabsorbed substance: glucose, amino acids

Question:

How would a diuretic (a drug that increases urination) be useful in the
treatment of heart failure?

Answer: They work by getting rid of the fluid that accumlates because of
edema due to the decrease in heart function

How would vasodilator drugs be useful in the treatment of heart failure?

Answer: Vasodilation causes a decrease in TPR.  This reduction causes a
decrease in the arterial blood pressure.  This in turn decreases the
pressure that the heart has to pump against.

Q - What three hormones are produced by the kidneys?  What are their
functions?

1.)   
A - 1.  Erythropoeitin - Increased production induces increased
erythrocyte production.
    2.  Renin - An enzyme that controls the formation of angiotensin
and influences blood pressure and sodium balance.
    3.  1,25-dihydroxyvitamin D - Influences Ca2+ balance in the
body. 

 

1.What disease may contribute to “sweet” smelling urine and how does this occur?

- Diabetes mellitus has been known to cause symptoms of sweet smelling urine.  This can be attributed to increased filtration in the glomerulus beyond that which can be reabsorbed.  The excess glucose is then secreted in the urine.

2.)    If the ascending and descending Loop of Henle suddenly became permeable to both water and sodium without discriminating against direction, what would be the result?

- There would no longer be a sodium gradient set up in the kidney and urine formation would result in an equilibration of the kidney with the urine.  NaCl and water would be lost in significant quantities from the body.

3.)    Alcohol, when consumed in large amounts, causes a great amount of urine to be excreted.  What is a possible explanation for this?

- Alcohol inhibits ADH production.  Without ADH, the kidneys are not able to reabsorb water in the collecting duct and a significant amount of water or dilute urine is excreted to the bladder.

Problem:
Which of the following situations would result in a decrease in the GFR?
a)an increased plasma concentration of ANP
b)the presence of protein in Bowman's capsule
c)vasodilation of the afferent arteriole
d)increased plasma colloid osmotic pressure resulting from dehydrating
diarrhea
e)increased MABP
*Answer: (d)

Problem: What do clearance values mean in relation to GFR?  What do they
reveal about how a particular substance is handled by the kidney?

Answer: If a substance's clearance value is equal to the GFR, it
indicates that it is being neither secreted or reabsorbed.  If its
clearance value is below the GFR, it is most likely being reabsorbed.
If the clearance value is above the GFR, the substance is most likely
being secreted.

Question:  Bob has been urinating a large volume each day(up to
25L/day).  When he went to see the doctor, they found out that he wasn't
producing vasopressin.  What is this condition called and why would he
be excreting so much urine?

Answer:  The condition is called diabetes insipidus and without
vasopressin, aquaporins couldn't be inserted into the collecting duct in
the nephrons so all of the GFR would be excreted since water can't be
reabsorped in the collecting duct.

Question:  What would it mean if GFR = RPC, and what might be an
example of such a molecule?

Answer:  This would mean that a certain molecule was be cleared at the
same rate it was filtered which would require active excretion.  Such a
substance might be an antibiotic or toxin.

Where are tight junctions in the nephron?  Where are they not as "tight" as in other locations?

Tight juctions are found between every epithelial cells in the nephron.  Tight junctions are looser in the proximal tubule to allow reabsorption. 

Questions:

1.  What are the 2 factors that stimulate vasopresson secretion? Induce
thirst?  How are these related?

The 2 factors for both are an increase in plasma volume (ECF) and an
increase in osmolarity of fluids.  These factors are not onlyrelated
because they induce both vasopressin secretiona and thirst, they both
recieve input to the same area of the brain, hypothalamus. 



2.  What is potentiation? 

It is the idea that when CCK and secretin are released, their effects of
pancreatic bicarbonate release (to buffer the HCl) are much higher
together than the individual components of each hormones' effects
separately. 

What is the difference between glycolysis, glycogenolysis and
gluconeogensis?

Glycolysis breaks down glucose
Glycogenolysis breaks down glycogen into glucose units
Gluconeogenisis breaks down the amino acids of something bigger to get
glucose

 

Problem and solution. Metabolic regulation: circle the correct choices (given in italics). Insulin is released by the liver/pancreas during the absorptive/postabsorptive state, affects cardiac muscle/brain/adipose tissue/ postural muscles/pancreas by stimulating/inhibiting target cells' vesicle fusion/exocytosis of GLUT-4 glucose transporters/receptors, causing plasma glucose levels to rise/fall.

1. When food enters the mouth __________ digests the carbs. The food travels down the ____ to the stomach. The___ is responsible for storing food. The ____ secretes mucus, pepsinogen, and gastrin. G cells are positively stimulated by _____ to release _____. This causes the chief cells to release _______ and the parietal cells to release ___ and -____. Pepsinogen is cleaved by _____ to ____.
   
   2. In the ____ phase, stimuli include sight, smell, taste and chewing ____ HCl secretion. Distension, an increase in peptides and decrease in the H+ concentration in the _____ phase causes a(n) ____ in HCl secretion. An increase in the H+, osmolarity, and an increase in [nutrient] in the duodenum in the _______ phase causes a(n) ______ in the HCl secretion.
   
   3. In the duodenum an increase in the H+, fat, amino acids and hypertonicity stimulate neural receptors via ______ neural reflexes to ____ parasymp. efferents in the CNS causing a(n) ______ in gastric emptying.
   
   Answers:
   1. amylase, esophagus, body, antrum, protein, gastrin, pepsinogen, HCl, intrinsic factor, pepsin
   2. cephalic, increase, gastric, increase, intestinal, decrease
   3. long, decr. incr.

QUESTION:
Describe each of the following processes as related to the post-
absorptive or absorptive states.  What type of process can it be
cateogrized as?  What substrates are involved?  What hormone regulates
it?  Where does it occur?

This was helpful in distinguishing the differences between the
processes.

1. Gluconeogenesis = conversion of fatty acids and amino acids to
glucose; a catabolic process stimulated by glucagon and occurring in
the liver

2. Glycogenesis = conversion of glucose to glycogen; an anabolic
process stimulated by insulin and occurring in liver and muscle

3. Glycogenolysis = conversion of glycogen to glucose; a catabolic
process stimulated by glucagon and occurring in liver and muscle

4. Lipolysis = conversion of triglycerides to fatty acids/glycerol to
glucose; a catabolic process stimulated by glucagon and occurring in
adipose and liver

5. Lipogenesis = conversion of glucose to fatty acids/glycerol to
triglycerides; an anabolic process stimulated by insulin and occurring
in adipose and liver

6. Proteolysis = conversion of proteins to amino acids to glucose; a
catabolic process stimulated by glucagon and occurring in muscle and
liver

7. Protein synthesis = conversion of amino acids to proteins; an
anabolic process stimulated by insulin and occurring in muscle

Q: What are the four basic GI pocesses?

A: Motility, secretion, digestion, and  absorption.

Q:  ______________(one of the GI processes) and ______________(another one of the GI processes) are regulated to maximize digestion and absorption. 

A: Motility and secretion

Q: What are the three phases of GI regulation, where do the take place, and are there hormonal influences?

A:

Q: What are the four phases of gastric motility?

A: Filling, storage, mixing, emptying

1.)    Acid reflux disease results in the presence of acid in the esophagus.  What might cause this and what would be a logical way to treat it?

- The presence of acid in the esophagus is likely due to a malfunction of the lower esophageal sphincter.  This is typically treated with antacid buffers as well as diet and lifestyle changes.

2.)    Pernicious anemia is the result of a deficiency of the vitamin B­₁₂ in the body.  What is likely the cause of the deficiency?

- Pernicious anemia is caused in most cases by the absence of intrinsic factor production by parietal cells.

3.)    Why do cells in the body secrete digestive enzymes in the form of precursors?

- If the body did not secrete digestive enzymes as precursors and they were synthesized in their active state, the digestive enzymes would digest the cells themselves!