Exam%203%20Key - Biology 252 - Exam 3 - DeSaix June 15,...

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Biology 252 -- Exam 3 -- DeSaix June 15, 2009 Name________________________ Print your name, last name first, legibly on your answer sheet. Fill in Bubbles for your name and PID. Each answer is worth 2 points. Always choose one best answer and use only number 2 pencils to fill in your answers. Be sure to sign the pledge on your answer sheet. The last question will be used only if another question has to be deleted. Turn in your scantron. Keep your test paper with answers. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The left ventricular wall of the heart is thicker than the right wall in order to ________. 1) A) accommodate a greater volume of blood B) expand the thoracic cage during diastole C) pump blood with greater pressure D) pump blood through a smaller valve Answer: C 2) Small muscle masses attached to the chordae tendineae are the ________. 2) A) trabeculae carneae B) pectinate muscles C) papillary muscles D) venae cavae Answer: C 3) If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells ________. 3) A) it would be much longer before cardiac cells could respond to a second stimulation B) contractions would last as long as the refractory period C) tetanic contractions might occur, which would stop the heart's pumping action D) it would be less than 1 - 2 ms Answer: C 4) Compared to skeletal muscle, cardiac muscle ________. 4) A) has gap junctions that allow it to act as a functional syncytium B) lacks striations C) has more nuclei per cell D) cells are larger than skeletal muscle cells Answer: A 5) If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________. 5) A) threshold is reached more quickly and heart rate would increase B) potassium channels compensate and no change in heart rate would occur C) heart rate would decrease, but blood pressure would rise due to the excess sodium present D) tetanic contraction would occur due to the short absolute refractory period of cardiac muscle Answer: A 1
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6) Which statement best describes arteries? 6) A) All carry oxygenated blood to the heart. B) All carry blood away from the heart. C) All contain valves to prevent the backflow of blood. D) Only large arteries are lined with endothelium. Answer: B 7) Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of ________. 7) A) arterioles B) arteries C) veins D) capillaries Answer: D 8) Select the correct statement about the movement of materials at the capillary level. 8) A) Oxygen diffuses up its concentration gradient. B)
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This note was uploaded on 11/04/2011 for the course BIOL 252 taught by Professor Johnson during the Fall '07 term at UNC.

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Exam%203%20Key - Biology 252 - Exam 3 - DeSaix June 15,...

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