Sample Exam 3 2006

Sample Exam 3 2006 - BIO 328 Sample Examination 3 4...

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BIO 328 Sample Examination 3 4 December 2006 FOR EACH QUESTION, SELECT THE MOST INCORRECT ANSWER Mark your answers on the op-scan sheet with a No.2 pencil. If you change your answer, be sure to erase thoroughly. There are 20 questions on this examination so be sure to answer all of them. Fill in your name and SBU ID number (NOT YOUR SS#) on the answer sheet. PRINT ON THE TOP OF YOUR ANSWER SHEET THE FIRST TWO WORDS OF QUESTION 1. 1. Cardiac muscle: a. A significant difference between SA nodal cells and ventricular muscle cells is that SA nodal cells possess voltage-gated Na + channels that open when SA nodal cell membranes are repolarizing. b. Cardiac muscle differs from smooth muscle in that myogenic stimuli do not induce contraction. c. The Ca ++ required for contraction is supplied by activation of voltage-gated Ca ++ channels in the sarcolemmal membrane and by the receptor-mediated Ca ++ -induced Ca ++ release from the sacroplasmic reticulum. d. Under normal conditions, cardiac muscle cannot be tetanized because the absolute refractory period of ventricular muscle cells is almost as long as the time needed for the chemical and mechanical events involved in tension development. e. Cardiac muscle is similar to smooth muscle in that calcium regulation of excitation- contraction coupling involves binding to troponin and myosin. 2. Mean arterial blood pressure (MAP, all variables not mentioned are held constant): a. Following a mild hemorrhage (10-20% blood volume loss), MAP is lower than pre- hemorrhage levels despite the fact that heart rate is higher than pre-hemorrhage levels. b. In orthostasis, the initial drop in MAP is principally associated with a drop in stroke volume due to decreased EDV. c. During mild to moderate exercise, total peripheral resistance decreases and MAP increases. d. In primary hypertension, MAP is chronically elevated because left ventricular hypertrophy causes abnormal, sustained increases in total peripheral resistance. e. Diuretics may decrease MAP because they decrease blood volume and cardiac output. 3. RAAS system: a. Elevated plasma levels of aldosterone will increase Na + reabsorption, in part, by causing an increase in the synthesis and insertion number of Na + ‘leak’ channels in the apical membrane of distal tubule cells. b. ACE inhibitors are sometimes an effective treatment for primary hypertension because they inhibit the enzyme catalyzing the chemical reaction responsible for the formation of angiotensin I. c. In hypovolemia, GFR decreases, renin secretion increases, and plasma angiotensin II levels increase. d. In hypervolemia, GFR increases, plasma angiotensin I levels decrease, and plasma aldosterone levels decrease. e.
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Sample Exam 3 2006 - BIO 328 Sample Examination 3 4...

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