Practice Exam II

Practice Exam II - 1 Practice Exam II, PNB 2250, 2008 1....

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1 Practice Exam II, PNB 2250, 2008 1. Smooth muscle cells A) have a poorly developed sarcoplasmic reticulum B) are triggered to contract by a lowering of cytosolic Ca 2+ C) are multinucleate D) have a well-developed sarcoplasmic reticulum E) have clearly visible striations 2. Single-unit smooth muscle A) action potentials result from regenerative K + potentials B) cells contract independently of each other C) action potentials spread from cell to cell through gap junctions D) action potentials spread from cell to cell through varicosities 3. Which of the following methods of initiating action potentials is used by cardiac muscle? A) end-plate potentials B) pacemaker potentials C) somatic motor neurons D) summation of EPSPs 4. Cardiac muscle A) lacks T tubules B) has no gap junctions C) is striated D) has very few mitochondria E) contains only thick contractile fibers 5. What anchors actin and myosin filaments to the plasma membrane in smooth muscle cells? A) z-lines B) &-actinin C) filamin domains D ) C a 2+
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2 6. Smooth and skeletal muscle develop about the same amount of tension per unit cross- sectional area, but A) smooth muscle can maintain tension over a greater length B) smooth muscle has longer myosin filaments C) smooth muscle lacks troponin D) smooth muscle myosin ATPase activity is very slow E) all of the above 7. Which of the following is not expected to cause smooth muscle relaxation? A) protein kinase C phosphorylation of phosphorylated myosin B) phosphatase dephosphorylation of myosin phosphate together with a decrease in intracellular Ca 2+ C) protein kinase C phosphorylation of caldesmon D) all of these will cause relaxation 8. Smooth muscle can undergo spontaneous contraction due to pacemaker potentials. Spontaneous depolarization in these cells is caused by A) protein kinase C B) an increasing K + conductance C) a regenerative opening of Ca 2+ channels in the plasma membrane D) a decreasing plasma membrane K + conductance 9. A cardiovascular system is required by large multi-cellular organisms because A) for large multi-cellular animals, mass specific metabolic rates are very high B) for animals greater than 0.5 mm radius, diffusion is more than sufficient to transfer nutrients and remove wastes C) for animals greater than 0.5 mm radius, diffusion is insufficient to transfer nutrients and remove wastes D) large animals produce so much waste per unit weight that a cardiovascular system is needed 10. Which of the following statements about closed circulatory systems is false ? A) closed circulatory systems can rapidly deliver nutrients to tissues B) closed circulatory systems can be high pressure systems C) closed circulatory systems are found in all vertebrates
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3 D) closed circulatory systems require a large volume of blood (20-40% of body volume) 11. Which of the following best describes the path that the cardiac action potential takes through the mammalian heart? A) atrioventricular node – sinoatrial node – atria – ventricles
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This note was uploaded on 11/16/2011 for the course PNB 2250 taught by Professor Renfro during the Spring '08 term at UConn.

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Practice Exam II - 1 Practice Exam II, PNB 2250, 2008 1....

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