1. You are an emergency medical technician (EMT) who has received a call from the local Dairy Queen. A customer with a heart condition has a highly elevated pulse rate. The suspected cause is an overdose of theobromine, a phosphodiesterase inhibitor found in chocolate. (Which means that cAMP levels remain high within the cells). Which of the following drugs in your first aid kit might help to lower his heart rate? Explain how it would work or why it wouldn't work. Think fast, but think carefully there's no time to lose!

Atropine (muscarinic blocker)-

Propanolol (beta blocker)-

Epinephrine-

Muscarine-

2. Draw a graph illustrating the membrane potential for the sinoatrial node. On the horizontal axis (which represents time), let the recording run for 15 seconds. At 10 seconds show the response to administration of norepinephrine. Briefly explain the mechanism of the norepinephrine response.

3. A friend of mine occasionally has problems with regularity (moving the bowels or eliminating feces). During one of her troubled times, my friend, let's call her Allison, asked if I had a cigarette. She claimed that a cigarette would help her to move her bowels. I thought about this for awhile and decided that it didn't make any physiological sense. (Other people have reported similar responses to chewing tobacco). Give me an explanation for a possible mechanism of this alleged action. Or if it doesn't make sense to you, explain why.

4. You are working in your lab late one night, when your assistant (Igor) brings in a cell culture he has been preparing and nurturing for weeks. Your research involves the control of vasoconstriction and Igor has prepared a pure culture of arterioles upon which you can test your various alpha receptor agonists. After hours of experimentation with all twenty of your vasoconstriction factors you find that the arterioles are not contracting and decide that, once again, Igor has bumbled and wasted your precious time. Instead of thinking of ways in which to remove his putty-like brain without his noticing, you should get to the bottom of his error. What or where was the most likely source of the arteriole cells that Igor originally harvested for culture? Explain briefly.

5. In an attempt to study vertebrate respiratory efficiency, you painlessly place highly sensitive oxygen probes in the pulmonary veins of a border collie (dog) and a gray duck (or goose). (At risk of insulting your intelligence, I'll remind you that the pulmonary vein drains the lungs in birds and mammals). The oxygen probes can detect very slight changes in blood oxygen levels instantaneously. Draw a graph of the recorded levels of oxygen in each animal's pulmonary vein over a one minute period. Label your graphs.

6. What are the basic elements of a neural reflex?

7. We have discussed a number of neural reflexes. Pick your favorite neural reflex mechanism (the one you know best) and carefully diagram in an organized fashion all pertinent nerves and anatomical structures, and label with short explanations of how it works. Don't forget to name the function of the reflex.

8. What are the advantages and disadvantages of a life style as an ectotherm? In which type of environment would it be best to be an endotherm?

9. At the beginning of the term I asked you to define death. Now that you have looked at many of the mechanisms involved in life, think at a very reduced level and see if you have a different perspective on what death is. For example, many of you said that life ended when the heart stops beating, but we know that the heart can be started again artificially. Some of you said death is when the brain is dead, but what does it mean, physiologically, to be brain dead? Yes, when the O2 supply is cut off, the brain "dies," but what does lack of O2 cause? Take your answer as far down (reductionistically) as you can.

10. Diagram and explain all the mechanisms and pathways involved in the cephalic phase of digestion.

11. Diagram the loading and unloading of the respiratory gases carried by hemoglobin in the RBC. More importantly, explain how it works and why it is beneficial all the way around.

12. Aside from surgical intervention, is it possible for a human to develop into a true hermaphrodite (possessing the sexual function of both males and females)? Explain your answer.

13. It should be quite apparent by now that calcium plays a significant role in many physiological mechanisms. Because of its importance, calcium must be regulated very precisely and have a large reserve that can be mobilized rapidly. Where is this large reserve and how is it mobilized? Name the glands and chemical signals involved.

14. The synthesis and secretion of testosterone from the Leydig cells (interstitial cells of the testes) is regulated by negative feedback at the level of the hypothalamus and pituitary. In this example testosterone is the feedback signal that inhibits secretion of LH-RH and/or LH. What mechanism monitors and regulates the rate of spermatogenesis; which hormones are involved?

15. During a single twitch in a muscle fiber, what is the mechanism that reduces tension and allows for relaxation of the fiber? Explain your answer.

16. What are muscular hydrostats and how do they work? Give an example and use a diagram to illustrate how specific movements can occur.

17. The three types of twitch skeletal muscle fibers (often called Types I, IIA, and IIB) have a host of characteristics that reflect certain rates of activity and metabolic requirements such as, fatigue rate, oxidative and glycolytic capacity, myosin ATPase activity, myoglobin content, capillary density, fiber diameter, and mitochondrial content. It is argued that one of these characteristics is rate-limiting and the other parameters are present to support the rate-limiting feature.

From the list in the preceding paragraph, choose the character that you believe is the rate-limiting feature of the muscle fibers. Argue that the character you chose is rate-limiting by illustrating how the other characters are there for functional support.

18. What happens when ATP is removed or is no longer produced in the muscle fiber? Does the muscle relax? Explain your answer.

19. You study the sliding filaments of muscles from Tasmanian Devils and you are interested in trying out new research tools. A new enzyme has been discovered in a meat tenderizer. This enzyme, tropase, has been shown to completely destroy both troponin and tropomyosin, leaving actin and myosin filaments intact. What type of results would you predict for simple muscle contraction (single twitch) experiments where you injected tropase into the muscle fiber? Explain your predictions.

20. There are several complications that arise as a result of severe insulin deficiency. Four of these have to do with the kidney and/or water balance: (1) glycosuria, presence of sugar in the urine; (2) polyuria, excessive urine production and diuresis (water loss); (3) polydipsia, excessive drinking of water ; and (4) dehydration, excessive loss of body water. Using your knowledge of pancreatic, hypothalamic, and renal function, explain how each of these reactions to insulin deficiency occur.

21. Human females (as well as female anole lizards, Anolis carolinensis) normally ovulate a single ovum from one ovary and then ovulate an ovum from the other ovary the following month. This is called alternating ovulation. It should strike you as being odd that a peptide hormone from the pituitary (FSH) which circulates throughout the entire body could possibly cause one ovary to respond and not the other, and then have the opposite situation occur the next month. With the knowledge you have attained thus far in the course, come up with a hypothesis as to how alternating ovulation could be regulated.

22. At a social gathering some friends of yours find out that you have taken a course in physiology (of course, they don't know what grade you received) . Immediately they assume you know all the answers to their dilemmas. Being the learned student of physiology you rise to the challenge and attempt to explain the following observations they have made.

Most of your friends have noted a post-coital increase in urine production (they pee more following sex). In addition, many of them (especially the guys) have observed that it is sometimes difficult to initiate urination immediately following orgasm. It seems to take a little longer than usual to start voiding the bladder. How do you account for these two observations?

23. Describe the urine osmolarity of the following animals. Use a term that compares their urine solute concentration to their plasma solute concentration (e.g. hyperosmotic, isosmotic, etc.). Also, indicate which nitrogenous waste compound is most likely their major excretory product (ammonia, urea, or uric acid).

A. Marine Mammal

B. Freshwater Salamander

C. Desert-Dwelling Tortoise

D. Marine Invertebrate (sea star)

E. Marine Fish

F. Frog Tadpole

24. How would you describe the osmolarity of the interstitial fluid immediately surrounding the proximal convoluted tubule? Explain your answer.

25. You are an emergency medical technician (EMT) who has received a call from Marriott. A First-year Carleton student with a heart condition has a highly elevated pulse rate. The suspected cause is an overdose of caffeine, a phosphodiesterase inhibitor found in Jolt® Cola and coffee. (This means that cAMP levels will remain high). Which of the following drugs in your first aid kit might help to lower his heart rate? For each drug, explain how it would work or why it wouldn't work. Think fast, but think carefully there's no time to lose!

Atropine (muscarinic blocker)-

Propanolol (beta blocker)-

Epinephrine-

Muscarine-

26. What is the role of carbonic anhydrase in the red blood cell? Why is this role important?

27. Draw a graph illustrating the membrane potential for a cell in the sinoatrial node. On the horizontal axis (which represents time), let the recording run for 15 seconds. At 10 seconds show the response of the membrane potential to administration of acetylcholine. Briefly explain the mechanism of the acetylcholine response.

28. For a physiology experiment you are asked to sit still and breathe through a mask that is attached to a hose (approx. 2 feet long and 2 inches in diameter). The other end of the hose is open to the air in the room. What effects would this treatment (wearing the mask and hose fitting) have on your respiration rate? Explain the physiological mechanisms involved.

29. You have designed a new drug (Provasoshut®) that acts as an agonist of alpha-adrenergic receptors. In most of the systems you have studied (e.g. capillary beds of the digestive system, liver, and fat tissue), Provasoshut® causes vasoconstriction that lasts for at least 15 minutes. However, when you tried the drug on the capillary beds of the contracting muscle of the frog leg prep in your physiology lab, the vasoconstriction lasted only 30 seconds! What is the best explanation for the short-lived action of Provasoshut® in this preparation?

30. Your seventy five year old uncle (great uncle) is a member of the polar bear club. Members of this testosterone-rich men's club have a habit of spending Saturday nights drinking alcohol and sitting in hot tubs. After a few drinks, some of these men like to jump out of the hot water and dive into the icy lake a few yards away. Your great uncle (who has relatives with a history of heart disease) has expressed a wish to join "the boys" in this fun. Carefully explain to him in physiological detail why this is not such a good idea, and in fact is probably a very deadly idea.

31. If one of the goals of the kidney is to conserve water, then what is the point of the elaborate nephron set up? Why not just get rid of the "urine" at the turn (curve) of the Loop of Henle? Explain carefully.

32. Because of your extreme curiosity of physiological function and your abundance of time and money, you check yourself into Northfield General Hospital. You complain of various false symptoms (there is nothing wrong with you physically, but your mental state is questionable) and the attending physician puts you on an intravenous saline drip (rate is 1 liter/hour). The solution is 0.9% saline, and therefore isotonic. Explain how your body will react to the administration of this solution. What specific mechanisms are involved?

33. What are the stimuli, signals, and targets involved with the digestion of fats (lipids)? Be specific and name the correct anatomical structures involved.

34. Diagram and label a single complete reflex circuit involved in the cephalic phase of gastric secretion. Include all relevant anatomical features.

35. Sympathetic stimulation of the heart causes an increase in heart rate and stroke volume, thereby increasing cardiac output. It is believed that stroke volume increases because there is greater coordination and synchronization of the myocardium. What is the mechanism of this heightened synchronicity? (Yes, this is tough, but you know the answer).

36. One of the effects of Diabetes mellitus is a rise in blood glucose concentrations. What specific effects would this have on the kidney? Explain.

37. Based on what you know about the three different types of skeletal muscle fibers, which one would generate the greatest tension? Why?

38. Where does renin come from and what stimulates its release?

39. As extracellular fluid (ECF) volume increases, what role(s) does the kidney play in allowing the body fluid volume to return to normal?

40. What is the job of the kidney in a freshwater fish? Would you expect it to have Loops of Henle? Explain.

41 You have high blood pressure. One way to lower blood pressure is with a diuretic that acts to inhibit ADH. If you have only two choices, alcohol or caffeine, which would you choose and why?

42. Carefully draw a line that represents a recording of the membrane potential of a myocardial cell (type III) from the ventricle of a mammalian heart during contraction. Show a recording that lasts for several seconds. Include axes and label them. Using a superimposed dashed line (or a different color ink), draw the membrane potential of the same cell during sympathetic stimulation. Label the differences between the two lines and indicate what caused these differences.

43. Explain to Jim Bob why the effect of caffeine on diuresis cannot be via direct action on the renal collecting ducts. (Do not state that you know the effect of caffeine is on the ADH secreting neurons of the hypothalamus, this is not the answer I want. Think mechanism.)

44. Lipids from a greasy meal enter your small intestine. What specific series of events does this stimulate and what are the specific effects?

45. Explain why it is not a good idea to deeply hyperventilate for a long period of time before you dive into the water to harvest some pearls.

46. How does carbonic anhydrase facilitate CO2 unloading from metabolically active tissue? Where is this enzyme found in this scenario?

47. Diagram, label, and explain the feedback regulation of testicular function in male (duh!) mammals.

48. A recent review article summarizing the interactions between blood pressure, atrial natriuretic hormone or peptide (ANH or ANP), and kidney function, suggests that the majority of ANH is released into the blood via stimulation from oxytocin. The proposed pathway is shown below. It is your job to test this hypothesis. What type of experiment would you devise to see if oxytocin is responsible for the increase of circulating ANH following an increase in blood pressure? You may purchase any hormone or hormone antagonist you can think of.

49. Look at the graph below. This is a look at the urine output and urine concentration of a vampire bat just before, during, and after a feeding event (they drink blood). Based on what you know about kidney function, what do you suspect is controlling the majority of these changes in kidney function. Explain. (The graph shows urine flow rate increasing almost vertically as urine concentration drops. Then, following cessation of feeding, urine concentration rises as urine output drops.)

50. TRIVIAL QUESTION: According to the question writers in Carleton's "Late Night Trivia," a pregnant goldfish is called a "twit." This is absurdly wrong in the world according to Matt. What should we call a pregnant goldfish?

Page author: Kristen Klemenhagen

Last updated: January 28, 2000

Questions? Contact Matt Rand