Introduction to Section II

Name: ______Biology 449 - Animal Physiology Fall 2007

Midterm 3 Fill in your scantron form as follows:  Write and bubble in your name in the upper left (last name first).  Sign your form in the upper right. By so doing you verify that you are abiding by Creighton’s policy on academic honesty.

Multiple choice: As always, choose the best answer for each multiple-choice question. Answer on your scantron form. Each question is worth 3 points.

1. A normal hemoglobin molecule consists of a. one heme group and one globin. b. one heme group and four globins. c. four heme groups and one globin. d. four heme groups and four globins. e. one iron atom.

2. Consider a volume of blood moving through the circulatory system from one capillary bed to another. Which of the following pieces of information would you need to determine if the hemoglobin would load or unload oxygen when it arrived at the second set of capillaries? a. The concentration of oxygen at the first set of capillaries. b. The concentration of oxygen at the second set of capillaries. c. The partial pressure of oxygen at the second set of capillaries. d. The concentration of oxygen at the first and second set of capillaries. e. The partial pressure of oxygen at the first and second set of capillaries.

3. Which of the following would normally have the lowest affinity for oxygen at a PO2 of 40 torr (i.e. normal resting tissue levels)? a. Myoglobin

b. Adult hemoglobin at normal PCO2 and pH

c. Adult hemoglobin following an increase in PCO2 d. Adult hemoglobin following an increase in pH e. Fetal hemoglobin

4. The carbamino compounds that help transport carbon dioxide in the blood are the result of CO2 combining with a. fatty acids. b. heme groups. c. peptides and proteins. d. phospholipids. e. water.

1 5. The layer of the gastrointestinal tract where the capillaries that absorb nutrients are found is the a. epithelial cell layer. b. mucosa. c. submucosa. d. smooth muscle. e. serosa.

6. If you were told that a particular substance underwent some digestion in both the mouth and small intestine, you could surmise that it was a. a fat. b. a protein. c. a starch. d. Potentially two of the above. e. Potentially all of the above.

7. Which of the following is a hormone that strongly promotes the release of sodium bicarbonate from the pancreas? a. Cholecystokinin b. Enterokinase c. Gastrin d. Secretin e. Zymogen

8. Which of the following statements about bile salts is not true? a. They are enzymes that break down fats. b. They have a hydrophilic component that interacts with water and a hydrophobic component that interacts with fat droplets. c. They are responsible for emulsification of fats. d. They are produced by the liver. e. All the above are true.

9. Which of the following do not initially pass through the liver after being absorbed from the small intestine? a. Amino acids b. Carbohydrates c. Fats d. Two of the above do not initially pass through the liver. e. All of the above do initially pass through the liver.

2 10. When glucose is absorbed from the small intestine, it moves across the apical membrane of the epithelial cells via a. permeation. b. facilitated diffusion by a uniport carrier. c. cotransport with Na+. - d. cotransport with HCO3 . e. active transport by a uniport carrier.

11. The urge to defecate is normally initiated by a. contraction of the internal anal sphincter. b. decreased volume within the large intestine. c. increased levels of the hormone rectokinin. d. mass movement of fecal material into the rectum. e. thinking happy thoughts.

12. One of the normal effects of an increase in leptin is a. increased appetite. b. increased storage of fats. c. increased metabolic rate. d. increased neuropeptide Y release. e. increased sleepiness.

13. Which of the following class of substances is not filtered into the nephron of the kidney from the glomerulus? a. Amino acids b. Ions c. Large proteins d. Monosaccharides e. Small toxins

14. A substance C enters the nephron from the glomerulus at a concentration of 10 µg per ml. If the glomerular filtration rate is 100 ml per minute and urine leaves the kidneys at the rate of 10 ml per minute, what should the final concentration of C be if it is neither secreted nor reabsorbed? a. 0.1 µg/ml b. 1 µg/ml c. 10 µg/ml d. 100 µg/ml e. 1000 µg/ml

3 f. Which of the following parts of the nephron is responsible for the maintenance of the concentration gradient in the renal medulla? g. Bowman’s capsule h. The proximal tubule i. The loop of Henle j. The distal tubule k. The collecting duct

15. The cellular-level effects of increased anti-diuretic hormone involve a. the insertion of aquaporins into the membrane of nephron epithelial cells. b. the removal of aquaporins from the membrane of nephron epithelial cells. c. the insertion of sodium transporters into the membrane of nephron epithelial cells. d. the removal of sodium transporters from the membrane of nephron epithelial cells. e. apoptosis of nephron epithelial cells.

16. Which of the following might result in abnormally low levels of blood sodium? a. Too high a level of angiotensinogen b. Overproduction of renin by the kidney c. Too much angiotensin converting enzyme in capillary beds d. The presence of a substance that prevents aldosterone from binding to its receptors e. All of the above might result in abnormally low levels of blood sodium.

17. Which of the following individuals would be most likely to show high levels of atrial natriuretic factor in her blood? a. Someone with low blood volume b. Someone with low blood sodium levels c. Someone with a low glomerular filtration rate d. Someone with high blood osmolarity e. Someone with high blood pressure

18. A person’s mean arterial pressure increases from 100 to 150 torr. After the kidneys have had time to response to this change, his glomerular filtration rate would likely a. drop to zero. b. decrease significantly. c. stay about the same. d. increase significantly. e. The glomerulus would probably explode.

4 f. Which of the following does not increase the release of renin by the granular cells of the juxtaglomerular apparatus? g. Increased blood pressure in the afferent arteriole of the glomerulus h. Decreased rate of sodium movement through the distal tubule i. Increased sympathetic stimulation of the granular cells j. Increased podocyte activity k. All of the above increase the release of renin.

Short answer: Write a concise answer to each of the following questions. Your answers should fit in the spaces provided. Diagrams may be used but must be accompanied by written explanations. Each question is worth 8 points.

19. Consider a person initially breathing normal air who then begins breathing a gas mixture with normal PO2 but a PCO2 of 50 torr (as opposed to the nearly zero torr in normal air).

20. What system do mammals use to detect changes in CO2 levels in the bloodstream?

21. What would be the effects of the new gas mixture on ventilation? Explain your answer.

5 22. Discuss the gastric enzyme pepsin. Where is it produced, what promotes its release, how is it activated, and what does it do?

23. During the post-absorptive phase, insulin levels are low and glucagon levels are high in the blood. What are the specific effects (as currently known) of each of these hormone levels on different types of tissue? 24. Effects of high glucagon:

25. Effects of low insulin:

6 26. Using a list or diagram, indicate the regions in the nephron where each of the following occur: i) water reabsorption, ii) passive reabsorption of NaCl, and iii) active reabsorption (active transport) of NaCl. Also note locations where these rates are variable.

27. Consider an individual who, on a dare, drinks three liters of an isosmotic saline solution. As the solution is absorbed across the wall of the GI tract it enters the bloodstream, substantially increasing blood volume. 28. If we initially assume there are no regulatory responses by the person’s body, what will be the effects of this change in blood volume on the cardiovascular system?

29. When regulatory responses did occur, what changes would we expect to see in the cardiovascular system, and what would control these changes?