PracticeExam4B

PracticeExam4B - BISC220 Exam 4 (Version B) Spring 2006...

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BISC220 – Exam 4 (Version B) Spring 2006 Herrera 1. Glands in the stomach secrete HCl and as a result, stomach contents released into the duodenum are extremely acidic. Briefly describe two mechanisms that act to prevent acidic damage to the duodenum. 2. Which one of the following statements is false? a. At this moment, as you as sitting there reading this question, blood pressure in capillaries in the lower part of your lung is higher than blood pressure in capillaries in the upper part of your lung. b. In each cardiac cycle, muscle cells near the apex (bottom) of the ventricles contract before muscle cells near the top of the ventricles. c. Aldosterone and atrial natriuretic hormone have similar effects on blood pressure. d. The fact that protein is not filtered into Bowman’s capsule contributes to reabsorption of water in the proximal tubule. 3. Victims of famine, especially children, typically show severe muscle wasting and swollen abdomens. Why are their abdomens swollen? a. Malnutrition renders the liver incapable of secreting sufficient plasma protein, resulting in less reabsorption of H 2 O into capillaries, so fluid accumulates in the abdomen. b. Severe malnutrition leads to progressive kidney failure, causing deficiencies in H 2 O excretion which lead to H 2 O accumulation in the body. c. Part of the stress response triggered by starvation involves over-secretion of aldosterone, causing excessive retention of Na + and H 2 O in the body. d. As muscles are catabolized to supply the starving body with energy, H 2 O and ions that were formerly part of muscle cytoplasm accumulate in the abdominal cavity. 4. Patients with advanced emphysema tend to be barrel-chested, i.e., the anterior-posterior diameter of their chest is expanded. In addition, the diaphragm is depressed, i.e., occupying a lower position than normal. Explain these symptoms. 5. Indicate whether each of the following statements is true or false. a. An increase in P CO2 would increase the affinity of hemoglobin for O 2 . b. If myoglobin is to serve as an efficient O 2 storage molecule in skeletal muscle, to be used when O 2 falls to low levels, one would expect that the affinity of myoglobin for O 2 would be lower than the affinity of hemoglobin for O 2 . c. Pressure in the interpleural space (between the outside of the lung and the inside of the chest wall) is always lower than atmospheric pressure. d. P O2 in the alveolar air is always less than P O2 in the ambient air. 6. T-cell receptors… a. trigger humoral immune responses when they bind antigens. b. are restricted to the cytoplasm or nucleus of T-cells. c. are important in defending the body against viral infections. d. are produced by plasma cells.
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e. only function if the cell has previously encountered the antigen.
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This note was uploaded on 04/25/2008 for the course BISC 220L taught by Professor Herrera,mcclure during the Spring '07 term at USC.

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PracticeExam4B - BISC220 Exam 4 (Version B) Spring 2006...

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