Vertebrate Physiology 437 EXAM III NAME, Section (circle): am pm 23 November Exam is worth 100 points. You have 75 minutes.

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1 1 Vertebrate Physiology 437 EXAM III NAME, Section (circle): am pm 23 November Exam is worth 100 points. You have 75 minutes. True or False (please write true or false ; 10 points total; 1 point each) 1. The impotence drug Viagra acts by inhibiting the breakdown of cgmp in the smooth muscle cells of appropriate arterioles. 2. The spleen is important for the diving ability of seals because it stores oxygenated red blood cells until they are needed by working tissues. 3. A cold lizard out basking in the morning sun uses right-to-left blood shunting to facilitate heat gain. 4. Incompetence (incomplete closure) of the left AV valve would lead to higher pressure in the left atrium. 5. Stimulation of the medullary respiratory center by decreased blood PCO 2 leads to increased phrenic nerve activity. 6. Humans can excrete urine with a U/P osmolar ratio of about Most oxygen in mammals is carried to working tissues from the lungs by being dissolved in the plasma. 8. Carbon dioxide production and protein metabolism are the primary contributors to the acid load in the body of most mammals. 9. The three main processes by which urine is formed in the mammalian kidney are filtration, reabsorption, and secretion. 10. The nephrons of bony fishes living in the ocean tend to have a higher relative filtration rate then the nephrons of their freshwater cousins. In the following table indicate the relative values (highest, middle, or lowest) for each of the three common types of nitrogenous waste products (you have to provide the other two waste products as well): [8 points] Type of Waste Solubility in Water Cost (ATP) to Produce 1 2 Urea middle 3 lowest

2 2 Shortest Answer (2 points each, 24 points total; ~a few words). 1. How do dogs pant without hyperventilating? 2. What painful injury does the Hering-Breuer reflex prevent? 3. Describe the role of pulmonary surfactant. 4. In the Wigger s Diagram of heart function, what events take place when pressure curves cross? 5. Given the following information, calculate cardiac output. MABP = 100 mm Hg HR = 50 beats/min EDV = 130 ml ESV = 80 ml 6. A) What ion is directly involved, and B) what ATPase protein is indirectly involved, in glucose reabsorption in the proximal tubule of the nephron? 7. Other than viscosity, list two important factors that determine the flow rate in a vessel. 8. Give two examples of countercurrent exchangers in vertebrates and indicate how they are important. 9. Describe two reasons why small endotherms have a difficult time maintaining appropriate water balance. 10. What does a BandIII protein do in the plasma membrane of red blood cells? 11. Would turtles overwintering at the bottom of ponds likely survive better in warmer water or cooler water? Why? 12. In the thigh of a hyena, what effect would increased levels of CO 2, temperature, and adenosine tend to have on nearby arteriolar smooth muscle?

3 3 Short Answer (3.5 points each, 31.5 points total; ~a few sentences) 1. How are alveoli and parabronchi different? Where would you find each? 2. Explain how the evolutionary origins of different groups (sharks, bony fishes, tetrapods) explain, in part, their different osmotic relations (e.g., iso, hyper, or hypo) to their surroundings. 3. If the major arteries in a mammal become more calcified and rigid with age, what happens to the variation (more or less variable?) in pressure at the level of the capillary beds? Why? 4. In humans with congestive heart failure, common complaints include shortness of breath (also called dyspnea) and fatigue. Please explain why failure of the heart to effectively pump blood out of the left ventricle might lead to these symptoms. 5. What keeps the ureteral urine of birds fairly unconcentrated? Why is dilute ureteral urine important?

4 4 6. What happens to the cranial blood pressure of terrestrial and aquatic snakes when subjected to the tilted head-up position under laboratory conditions? What morphological differences lead to the different responses in terrestrial versus aquatic snakes? 7. What are chordae tendinae and what is their role? 8. Why is carbonic anhydrase an important enzyme in many vertebrates? 9. Explain the Frank-Starling mechanism.

5 5 Visual Answer (CHOOSE ONE of the TWO, 6 points) 1. Using the left set of axes, draw and label the action potential for a ventricular muscle cell. Three ions are each primarily responsible for the three most distinctive phases of this action potential. Please identify these phases with their appropriate ion. Please label your axes appropriately, including the approximate scales. Now, draw another action potential for an SA node cell that illustrates the differences between muscle cells and SA node cells (no need to label; we will assume the scales are the same). 2. Draw the oxygen dissociation curve for hemoglobin. Label the axes appropriately, including the approximate scale. Briefly explain the significance of the shape of the curve. Would the Bohr Effect act to shift the oxygen dissociation curve to the right or to the left? How would the presence of CO (carbon monoxide) shift the curve? Now add the oxygen dissociation curve of myoglobin to your graph (make sure we can tell which curve is which).

6 6 Long Answer (CHOOSE TWO of the THREE ; 5 points each, 10 points total; ~a paragraph). 1. Describe the cascade of events triggered by renin release. 2. Describe short term and longer term adjustments of mammalian physiology to hypoxic conditions (e.g., at high altitude). 3. How do shark rectal glands excrete excess salt? Please include discussion of transporters, ion gradients, etc. A diagram may be helpful.

7 7 Longest Answer (10.5 points; ~a couple of paragraphs). Briefly describe the 4 or 5 main anatomical features of the functional unit of the kidney. Adding in the collecting duct to your description, describe how the concentration gradient within the kidney is established (higher osmolarity towards center of kidney/renal pelvis as observed in the interstitial fluid of the kidney). A diagram may be helpful. Explain the opposite effects of starvation and kidney stones on urine volume.