Download SHORT ANSWER/APPLICATION QUESTIONS

Checklist for Exam 2 – Biology 2424 - Human Physiology
Use this list to help you prepare for exam 2. I will use several of these questions exactly as you see them here on the exam for the
short answer/application section. Others will be embedded in the multiple choice section of the exam. Some material on this list may
not be covered or may not be listed depending on where we get in lecture. This is a good starting place however.
1. (a) List the steps that must occur in order for an action potential to be generated and propagated in a myelinated axon. You may use
a diagram to help you in your answer. Correctly include in your answer a discussion of sodium and potassium, channel proteins, gated
channels, absolute and relative refractory periods, depolarization, repolarization and hyperpolarization, and sodium-potassium pump.
(b) List the types of cells that can generate action potentials
2. (a) List the proper sequence of events that occurs when an action potential reaches the synaptic bulb (bouton). (b) Describe the
possible alterations in the membrane potential that might occur in the postsynaptic cell.
3. Many potent biological warfare agents like “nerve gas” inhibit the action of acetycholinesterase. (a) Explain physiologically how
the nerve gas works at the cellular level (You may use a diagram with labels if you wish). The (b) explain how the nerve gas works to
kill its victims. Finally (c) suggest a specific method of treatment for soldiers who are exposed to such a horrid toxin and how it
works. (Hint remember what neurotransmitters are used for the autonomic nervous system and for skeletal muscle contraction and
what these divisions of the nervous system do).
4. The colorful poison arrow frogs (Family Dendrobatidae) of South America are used by some of the natives to poison the tips of
their blow darts which they then use to hunt for game. The poison, dendrobatin, works by causing voltage-regulated sodium gates in
neurons to open and stay open indefinitely. Using your knowledge of anatomy and physiology, explain (a) what effect would the
poison have on the neurons of the prey items they were hunting by causing the sodium gates to stay closed, (b) what effect would it
have systemically (the whole body), and (c) why does it ultimately cause death?
5. The Japanese puffer fish is considered a delicacy in the island nation. However if it is not prepared carefully, the toxin contained in
the spines can be accidentally ingested. The toxin, tetrodotoxin, works by causing voltage-regulated sodium gates in neurons to close
stay closed indefinitely (i.e blocking the voltage gated Nat + channels). Using your knowledge of anatomy and physiology, explain (a)
what effect the toxin would have on the neurons of the humans that ingested it, (b) what effect would it have systemically (on the
whole body), and (c) why does it ultimately cause death?
6. (a) List 5 functional areas of the cerebral cortex and (b) describe their location and (c) the specific function of each of each area.
7. Most humans undergo short bouts of depression, but in many cases the effects are prolonged and can last years. (a) Explain 2
possible physiological causes for prolonged depression. (You may use a diagram with labels if you wish). Then (b) explain how
these physiological mechanisms can affect a person’s behavior. Finally (c) suggest a specific method of treatment and describe how it
works.
8. Lomotil (Immodium) is an effective cholinergic receptor blocking agent that inactivates smooth muscle and hence functions quite
efficiently as an antidiarrheal. Skeletal and cardiac muscles are also activated by cholinergic receptors yet Lomotil does not influence
either muscle type. (a) Explain why this is true based on what you know about neurotransmitters and receptor in the autonomic vs.
somatic motor divisions of the peripheral nervous system.
9. Mary is having difficulty with her first birth. All of her Lamaze training just doesn’t seem to be working and she is in terrible pain.
The smooth muscle contractions in her uterus (argued by some to be among the most powerful in the body) are causing her great pain.
She finally gives up on this “natural child-birth stuff” and opts for the ol’ fashion goodness of drugs. Her physician comes in and
performs a subdural injection of Novacaine in the lower lumbar regions of the spinal cord. (a) Explain what effect would this have on
Mary’s perception of uterine contractions? (b) Explain what the mechanism of action of this drug and how it works using what you
know of neurons, neurotransmitters, receptors, and the specific part of the brain involved.
10. (a) List the 12 cranial nerves (name and number), (b) whether they are sensory, motor, or mixed (both), and (c) what structures
they innervate (in general). You may arrange your answer in a table if you wish.
11. In most team sports defense is almost always more difficult to play the offense. Explain why this is by (a) providing a physiological
explanation using a (b) labeled diagram of neural pathways.
12. (a) List the sequence of events that describe how muscles contract starting from the motor neuron stimulating the muscle and
finishing with relaxation in the excitation-contraction coupling sequence. (b) Now describe the events that occur in the muscles to
actually shorten the sarcomeres using what you know about the sliding filament theory.
13. Determined to get in shape after binging on steady diet of Cheetos and cheap Beer (i.e. Lone Star and Pearl Light) during spring
break you decide to go to the gym. You are bound and determined to build muscle bulk. (a) Describe what exercises are best at
building muscle mass/bulk using what you know about the different types of muscle contractions? (b) Then explain why this is. (c)
Explain what happens on the inside of your muscles when they increase in size. The day after you go to the gym you can barely walk
because your muscles are so sore. (d) Explain what the difference is between muscle soreness/pain and muscle fatigue using
physiological references. Finally (e) describe what caused your delayed onset muscle soreness (DOMS) and (f) what you can do to
ease the pain (that has been verified by scientific studies).
14. Arnold, a body builder, movie-star, governor, and all-around tough guy, is justifiably proud of his development and definition in
his arms. Arnold breaks his left arm in a skiing accident, and is shocked when his cast comes off eight weeks later. You are his
extremely well paid personal athletic trainer/ physical therapist/ nurse/ doctor/ etc., and he predictably asks you to answer the
following questions in a thick Austrian accent. Please answer Arnold before he p-ownds yu into da gr-ownd (pounds you into the
ground)!
A. Vy ist mein left ahm zo zmall? (Why is my left arm so small)?
B. Vas ist diesen condition`called? (What is this condition called)?
C. Can it come back to normal? (You get the idea).
D. What is the condition called when muscles get bigger?
E. What must I do to ensure it does? Why? (Explain).
F. What is happening on the inside of my muscles (from a physiological standpoint) when they “grow or get bigger?” (Explain
using physiological terms).
15. Given that there are dozens of hormones released into the circulating blood at any given point in time and hence virtually all cells
are bathed with this conglomerate of hormones, (a) why do only certain cells respond? (b) Be sure to review your endocrine system
handout available on-line.
16. You have probably heard of “calcium channel blockers” being used to lower blood pressure in chronic hypertension. Fortunately,
these drugs are very specific to the subtype of calcium channels found in cardiac muscle. If at higher doses these drugs also blocked
calcium channels in neural cells, (a) what do you think would be the cause of death in an over-dose situation. Justify your answer
with respect to what you know about the functioning of the nervous system at the cellular level.
17. If human babies’ muscles and neurons are fully developed and functional at birth, why can’t they focus their eyes, sit up, or learn
to crawl within hours of being born? (Hint: muscle strength is not the problem).
18. It is possible for a person to appear “drunk” without drinking a drop of ethanol (ethyl alcohol – the kind found in alcoholic
drinks). Curious you decide to drink gallons of red Kool-aid until you start “catchin’ a nice buzz.” (a) Explain how this is possible
and (b) why it can potentially be lethal. (c) Now explain how a kool-aid buzz different from one produced by alcohol?
19. (a) Describe the different types of muscle contractions we discussed in class (isotonic/isometric/concentric/eccentric). (b) List
some “weight room” exercises that demonstrate each of these types of contractions. (c). Which type(s) of contraction are more
beneficial in building muscle mass? (d) Why is this?
20. Believe it or not San Angelo, Texas and Tom Green county has the highest rate of new Multiple Sclerosis (MS) diagnoses (per
capita) in the country. As coaches, nurses, and counselors you should be familiar with this often crippling disease. (a) Describe what
this disease is from a neuro-muscular standpoint (b) what the symptoms are and (c) what treatments are most common. The primary
diagnostic symptom of Multiple Sclerosis (MS) is the formation of plaques within Schwann sheaths of the peripheral nervous system.
Oddly, not until the latter portions of the disease is there any neuronal degradation. If the neurons are fine, (d) why is it then that
individuals with MS have difficulty in coordinating motions? Finally (e) what is the difference between MS and Muscular Dystrophy
(MD)?
21. (a) What does muscle actually mean in Latin? (b) What is the origin of the word? (c)Why are skeletal muscles red?
22. (a) What is a reflex? (b) Are reflexes homeostatic? (c) List the components of a typical spinal reflex arc using the withdrawal
reflex as an example.
23. Upon death skeletal muscles stiffen and “lock in place” in state known as rigor mortis. This process occurs approximately 3 to 4
hours after death with peak rigidity occurring after 12 hours. Gradually this stiffness dissipates over the next 48 to 60 hours and the
muscles become “loose” again. (a) Explain physiologically what causes this stiffness. Then (b) explain physiologically what causes
the muscles to eventually loosen. (Hint: think about the sequence of processes in muscle contraction and relaxation, ATP
use/production, and protein structure characteristics).