Biology Animal Physiology Fall Midterm 2

Transcription

1 Name: Biology Animal Physiology Fall 2011 Fill in your scantron form as follows: Midterm 2 Write and bubble in your name in the upper left (last name first). Sign your form on the upper right. By so doing you verify that you are abiding by Creighton s policy on academic honesty. Multiple choice: As always, choose the best answer for each multiple-choice question. Answer on your scantron form. Each question is worth 3 points. 1. Steroid hormones are released from the a. adrenal medulla. b. gonads. c. thyroid gland. d. Two of the above e. All of the above 2. Which of the following is not a common effect of hormones? (Note that hormones includes lipophobic and lipophilic hormones.) a. Changing membrane potential. b. Activating or deactivating enzymes to influence biochemical pathways. c. Altering gene expression rates. d. Only one of the above is a common effect of hormones. e. All of the above are common effects of hormones. 3. Which of the following is not (as far as we know) a tropic hormone? a. Adrenocorticotropic hormone b. Gonadotropin releasing hormone c. Growth hormone d. Prolactin e. Thyroid stimulating hormone 4. One of the major effects of the hormone cortisol is to a. increase cardiac output. b. increase the strength of the immune response c. mobilize energy for use by the body. d. suppress anxiety. e. make money for people selling bogus cortisol blockers on late-night TV. 1

2 5. Thyroid hormones help to increase body temperature by a. increasing shivering rates. b. increasing vasoconstriction. c. increasing Na + /K + ATPase activity. d. increasing temperature setpoint. e. decreasing the rate of sweat production. 6. Which of the following best describes the process by which long bones, like your femur, grow in length at the epiphyseal plates? a. Chondrocytes lengthen the diaphysis (shaft) by producing cartilage on the side of the plate closest to the end of the bone; osteoblasts later replace the cartilage with bone. b. Chondrocytes lengthen the diaphysis by producing cartilage on the side of the plate closest to the end of the bone; osteoclasts later replace the cartilage with bone. c. Chondrocytes lengthen the diaphysis by producing cartilage on the side of the plate closest to the middle of the bone; osteoblasts later replace the cartilage with bone. d. Chondrocytes lengthen the diaphysis by producing cartilage on the side of the plate closest to the middle of the bone; osteoclasts later replace the cartilage with bone. e. Hint : Do not choose answer e. It is not correct. 7. Which of the following gives the correct sequence of muscle components ordered from smallest to largest? a. Sarcomere, thick filament, myofibril b. Sarcomere, myofibril, thick filament c. Myofibril, sarcomere, thick filament d. Thick filament, myofibril, sarcomere e. Thick filament, sarcomere, myofibril 8. Imagine a muscle fiber with a mutant form of troponin that never changes conformation from its non-activated state. Which of the following best describes the first problem that would be encountered when this muscle is stimulated by a motor neuron? a. The fiber would not be able to generate action potentials. b. The sarcoplasmic reticulum would not be able to release Ca 2+. c. The Ca 2+ would not reach the myofibrils. d. Cross-bridge cycling would not occur. e. The fiber would not be able to stop contracting. 9. During the cross-bridge cycle in muscles, which step occurs immediately before ATP attaches to myosin? a. The myosin head moves from the low- to high-energy conformation. b. The myosin head moves from high- to low-energy conformation. c. The ATP is hydrolyzed to form ADP and P i. d. The myosin attaches to actin. e. The myosin dissociates from actin. 2

3 10. Consider the following graph showing an isometric twitch contraction in a muscle, triggered by an action potential at time t = Force (N) Time (ms) For this contraction, the latent period is about a. 0 ms. b. 80 ms. c. 100 ms. d. 260 ms. e. 280 ms. 11. Consider a muscle required to lift differing amounts of weight during a twitch contraction under isotonic conditions. Which of the following best describes the expected pattern as the weights increase? a. Shortening velocity increases, distance shortened decreases. b. Shortening velocity increases, distance shortened remains constant. c. Shortening velocity decreases, distance shortened decreases. d. Shortening velocity decreases, distance shortened remains constant. e. Shortening velocity remains constant, distance shortened remains constant. 12. Which of the following statements about motor units is false a. A motor unit is innervated by a single motor neuron. b. All the fibers in a motor unit are activated at the same time. c. It is not possible to activate some fibers in a motor unit and not others. d. Motor units containing oxidative fibers are normally activated before ones with glycolytic fibers. e. Motor units with oxidative fibers generally have more fibers per motor unit than those with glycolytic fibers. 3

4 13. Which of the following best describes the pattern as blood passes through the capillaries? a. Pressure averages about 100 torr; blood velocity is relatively fast b. Pressure averages about 100 torr; blood velocity is relatively slow. c. Pressure averages about 25 torr; blood velocity is relatively fast. d. Pressure averages about 25 torr; blood velocity is relatively slow. e. Pressure averages about 5 torr; blood velocity is relatively slow. 14. During a heartbeat, the closing of the atrioventricular valves is caused by a. pressure generated by atrial filling of the ventricles. b. pressure generated by the ventricles at the start of ventricular contraction. c. pressure in the arteries as ventricular pressure drops during ventricular relaxation. d. contraction of smooth muscle in the atrioventricular valves. e. insertion of a size 2 rubber stopper. 15. During a heartbeat in a person at rest, most of the movement of blood into the ventricles occurs during a. ventricular systole. b. ventricular diastole prior to atrial systole. c. atrial systole. d. I can t think of any more possible answers. e. Wait, I ll make one up ventricular fantastole. 16. Which of the following substances normally moves across the capillary endothelium by vesicular transport (endocytosis and exocytosis)? a. Oxygen and carbon dioxide b. Na + and K + c. Water d. Steroid hormones e. Proteins other than plasma proteins 17. The movement of lymph through the lymphatic system is accomplished by a. peristaltic contraction of the lymphatic vessels. b. compression of the lymphatic vessels by the surrounding skeletal muscles. c. beating of the two-chambered lymphatic heart. d. Two of the above. e. All of the above. 18. In the lungs, the major location of gas exchange with the blood is the a. trachea. b. bronchi. c. bronchioles. d. alveoli. e. More than one of the above is important in gas exchange. 4

5 19. An adult male s tidal volume is 750 ml and his ventilation frequency is 20 breaths per minute. What is his approximate alveolar ventilation rate? [I hope you can calculate this by hand, but if you need a calculator please ask me. Do not use your own calculator without my okay.] a. 500 ml/min b. 750 ml/min c ml/min d ml/min e ml/min 20. During a forceful exhalation, which of the following muscles would be activated? a. The diaphragm b. External intercostals c. Internal intercostals d. a and b e. a and c Short answer: Write a concise answer to each of the following questions. Your answers should fit in the spaces provided. Diagrams may be used but must be accompanied by written explanations. Each question is worth 8 points. 21. Complete the following table by indicating the relative value of each characteristic of muscle fibers in fast glycolytic versus slow oxidative fibers. Characteristic Fast glycolytic Slow oxidative Force production Myosin-ATPase activity Predominant metabolism Mitochondrial density Myoglobin content Glycogen stores Rate of fatigue Fiber diameter 5

6 22. Describe or diagram the hormonal pathway associated with growth hormone release. Be certain that general effects of each hormone in the pathway are clear. (You do not need to detail all the effects of growth hormone.) What would be the expected effects in an adult of a tumor that resulted in the release of excessive growth hormone? Answer with regard to both the hormonal pathway you diagrammed above and bone growth. 6

7 23. Describe the electrical events in the heart during a normal heartbeat. Include a brief indication of the muscular activity that results. You do not need to describe the resulting blood movements. What are the effects of the sympathetic and parasympathetic systems on pacemaker cells, to the level of detail we discussed in class? (This answer should be fairly short!) 7

8 24. Two questions relating to blood flow and pressure: a. Provide Poiseuille s law, explaining what each variable is. Which variable normally has the strongest effect on flow (or changes in flow) in the circulatory system? b. Qualitatively, what would be the effect on mean arterial pressure if one set of blood vessels vasodilates and no other changes occur in the cardiovascular system? Then, what are the expected responses in the cardiovascular system in a normal individual? 25. During a normal, resting inhalation, what are the expected changes in the intrapleural pressure and alveolar pressure? Briefly, what causes these changes, and what is the effect of each change? 8