PHYSIOLOGY MeQ'S (Morgan) All the following statements related to blood volume are correct except for: 5 A. Blood volume is about 5 litres. B.

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1 PHYSIOLOGY MeQ'S (Morgan) Chapter 5 All the following statements related to capillary Starling's forces are correct except for: 1 A. Hydrostatic pressure at arterial end is greater than at venous end. B. Hydrostatic pressure at arterial and is approximately 55 mmhg. C. Hydrostatic pressure at venous end is approximately 15 mmhg. D. Colloid osmotic pressure at arterial end is approximately 26 mmhg. E. Interstitial hydrostatic pressure is about 1-2 mmhg. All the following statements related to blood volume are correct except for: 5 A. Blood volume is about 5 litres. B. Haematocrit (Hc) is about 43%. C: Plasma volume is about 3 litres. D. Blood volume = plasma volume (100 - He) E. Heart contains about 7% of blood volume. A young male aged 18 has a brachial artery pressure of 125/80 mmhg. All of the following statements are correct except for: 17 A. The pressure in the left ventricle during diastole is about 0 mmhg. B. The pressure in the right ventricle during diastole is about 0 mmhg. C. The pressure in the right ventricle during systole is about 20 mmhg. D. The pressure in the left ventricle during systole is about 140 mmhg. E. The pressure in the ascending aorta during systole is about 110 mmhg. All the following statements related to cardiac output and blood flow are correct except for: 25 A. The peak pressure developed in the left ventricle is just before closure of the aortic valve. B. C. The mitral valve opens at the same time as the aortic valve closes. Blood flow into the ventricles is greatest as soon as the mitral and tricuspid valves open. D. Increased aortic pressure (afterload) increases ventricular work. E. Increased ventricular filling increases cardiac output. All the following statements related to blood flow are correct except for: 41 A. Resistance to blood flow is inversely proportional to radius4 (r4) B. Resistance to blood flow is increased by a high haematocrit. C. Resistance to blood flow is increased by a high viscosity. D. Haematocrit is an important determinant of blood viscosity. E. Resistance to blood flow increases with increased pulse pressure. Chapter 6 1

2 All of the following statements related to lung volumes in the "typical" normal person are correct except for: 1 A. Usual tidal volume is about 0.5 litres. B. Inspiratory reserve volume is about 3 litres. C. Residual volume is about 1.2 litres. D. Expiratory reserve volume is about 1.1 litres. E. Vital capacity is about 3.5 litres. All of the following statements related to respiration and lungs are correct except for: 5 A. Total lung volume is about 5.8 litres. B. Anatomical dead space is about 0.15 litres. C. In healthy subjects the physiological dead space is less than the anatomical dead space. D. The physiological dead space is greater than the anatomical dead space in lung disease. E. AilWays resistance decreases during exercise. Pretest Cellular Physiology: Which of the following characteristics of an axon is most dependent on its diameter: 1 A. Its resting potential. B. The duration of its refractory period. C. The conduction velocity of its action potential. D. The overshoot of its action potential. E. The activity of its sodium-potassium pump. If the extracellular K+ concentration is increased from 4 meq/l to 10 meq/l, 3 A. The membrane potential will become more negative. B. The sodium conductance will increase. C. The potassium conductance will increase. D. The membrane will become more excitable. E. The Na-K pump will become activated. The membrane potential will depolarize by the greatest amount if the membrane permeability increases for: 23 A. potassium 2

3 B. sodium and potassium. C. chloride. D. potassium and chloride E. sodium, potassium and chloride If the membrane conductances for sodium and potassium are equal, the membrane potential is close to: 25 A. -90 mv B. -70 mv C. -15 mv D. OmV E +40 mv During the relative refractory period: 27 A. the rate of depolarization is decreased B. the rate of repolarization is increased C. the threshold for eliciting an action potential is decreased D. the conductance of potassium is decreased E. the magnitude of the overshoot is increased The sodium gradient across the nerve cell membrane is: 30 A. a result of the Donnan equilibrium B. significantly changed during an action potential C. used as a source of energy for the transport of other ions D. an important determinant of the resting membrane potential E. maintained by a Na-Ca exchanger Increasing the extracellular potassium concentration will: 31 A. increase the threshold for eliciting an action potential B. hyperpolarize the membrane potential C. decrease potassium permeability D. decrease the activity of the sodium-potassium pump E. do none of the above Excitation-contraction coupling in skeletal muscle involves all the following events EXCEPT: 34 A. generation of end-plate potential B. binding of Ca++ to myosin C. formation of cross-linkages between actin and myosin D. depolarization along transverse tubules E. hydrolysis of ATP to ADP Correct comparisons between fast- and slow-twitch skeletal muscle fibres include all the following EXCEPT: 35 A. fasdt-twitch fibres fatigue more rapidly B. fast-twitch fibres develop more force C. fast-twitch fibres store more glycogen 3

4 D. fast-twitch fibres require a higher frequency of stimulation to produce tetanus E. fast-twitch fibres contain a higher concentration of mitochondria In a test subject, oxygen consumption was measured at 700 mllmin. Pulmonary artery oxygen content was 140 ml per litre of blood and brachial artery oxygen content was 210 ml per liter of blood. Cardiac output was which of the following? 45 A. 4.2 Llmin B. 7.0 Llmin C Llmin D Llmin E Llmin Which one of the following is the best index of preload? 46 A. Blood volume B. Central venous pressure C. Pulmonary capillary wedge pressure D. Left ventricular end-diastolic volume E. Left ventricular end-diastolic pressure Which one of the following is the best index of afterload? 47 A. Left ventricular end-diastolic pressure B. Left ventricular mean systolic pressure C. Pulmonary capillary wedge pressure D. Total peripheral resistance E. Mean arterial blood pressure During ventricular ejection, the pressure difference smallest in magnitude is between the: 51 A. pulmonary artery and left atrium B. right ventricle and right atrium C. left ventricle and aorta D. left ventricle and left atrium E. aorta and capillaries The greatest benefit derived from administering a positive inotropic drug to patient in heart failure results from: 56 A. a reduction in heart rate B. a reduction in heart size C. an increase in end-diastolic pressure D. an increase in wall thickness E. an increase in cardiac excitability At which point on the pressure volume curve illustrated below is the afterload on the heart the greatest? 57 o E 4

5 PRESSURE c A\ VOLUME A. a B. b c. c D. d E. e Closure of the aortic valve occurs at the onset of which phase of the cardiac cycle? 58 A. isovolumetric contraction B. rapid ejection C. protodiastole D. Isovolumetric relaxation E. rapid filling Which of the following will be greater during the plateau phase of the ventricular action potential than at rest? 65 A. sodium conductance B. total membrane conductance C. potassium conductance D. calcium conductance E. chloride conductance During exercise there is an increase in a person's 68 A. stroke volume B. diastolic pressure C. pulmonary artery pressure D. pulmonary arterial resistance E. total peripheral resistance If, under resting conditions, the heart rate is 70 beats per minute, the cardiac output is 5.6 Limin, and the end-diastolic volume is 160 ml, what is the ejection fraction? 69 A B C D E

6 Phase 4 depolarization of SA nodal cells is caused by: 70 A. an increase in the flow of sodium into the cell B. a decrease in the flow of potassium out of the cell C. an increase in the activity of the Na-Ca exchanger D. a decrease in the flow of chloride out of the cell E. a decrease in the activity of the Na-K pump Cardiovascular changes that occur during inspiration include decreased: 71 right ventricular filling B. right ventricular output A. C. pressure gradient from extrathoracic veins to the right atrium D. systemic arterial pressure E. left ventricular contractility All of the following would be greater than normal in a person with a dilated failing left ventricle EXCEPT: 79 A. pulmonary capillary hydrostatic pressure B. left ventricular wall tension B. left ventricular energy consumption D. left ventricular end-diastolic pressure E. left ventricular ejection fraction An increase in all the following would contribute to an increase in wall stress EXCEPT: 81 A. end-diastolic volume B. transmural pressure across the ventricle C. the thickness of the ventricular wall D. total peripheral resistance E. aortic pressure For each condition listed, select the lettered point on the Frank-Starling curves shown below with which it is most likely to be associated. (Assume point C is the resting state.) Stroke volume B 6

7 E Ventricular End-Diastolic Volume Increase in blood volume. 95 Myocardial effusion. 96 Pericardial effusion. 97 Decreased afterload. 98 Immediate compensatory reactions to haemorrhagic shock include: 101 A. decreased peripheral resistance B. constriction of the vessels of the brain and heart C. reduced levels of circulating catecholamines D. excessive loss of Na+ in the urine E. none of the above The constriction of a blood vessel to one-half of its resting diameter would increase its resistance to blood flow by a factor of: B. 4 C. 8 D. 12 E. 16 A. Which one of the following would cause a reduction in arterial pulse pressure?104 A. A decrease in arterial compliance B. A decrease in venous compliance C. A decrease in blood volume D. An increase in central venous pressure E. An increase in myocardial contractility When a person moves from the supine position to the standing position, there is an increase in: 105 A. central venous pressure B. preload C. heart rate d. the frequency of depolarization in the carotid sinus nerve E. stroke volume Central venous pressure is increased by: 107 A. decreasing blood volume B. increasing venous compliance C. increasing total peripheral resistance 7

8 D. decreasing heart rate E. decreasing plasma aldosterone concentration The increase in skeletal muscle blood flow that occurs during vigorous aerobic exercise: 108 A. causes an increase in total peripheral resistance B. causes an increase in blood pressure C. is primarily due to parasympathetic stimulation of skeletal muscle resistance vessels D. is primarily due to sympathetic stimulation of blood vessels E. is primarily the result of the accumulation of vasoactive metabolites A reduction in carotid sinus pressure would cause a decrease in: 111 A. heart rate B. myocardial contractility C. total peripheral resistance D. venous capacitance E. cardiac output Which of the following organs has the highest arteriovenous 02 difference under normal resting conditions? 112 A. Brain B. Heart C. Skeletal muscle D. Kidney E. Stomach The percentage of the total cardiac output distributed to any single organ is most dependent on: 113 A. the contractile state of the heart B. the magnitude of mean blood pressure C. the magnitude of diastolic pressure D. the ratio of an organ's vascular resistance to total peripheral resistance (TPR) E. the magnitude of cardiac output At which of the following sites does the blood flow lose the greatest amount of energy? 114 A. Mitral valve B. Large arteries C. Arterioles D. Capillaries E. Venules Which of the following changes in perfusion of an organ system is an example of autoregulation? 123 A. The decrease in renal blood flow during haemorrhage B. The decrease in blood flow to the skin during exposure to a cold environment C. The increase in coronary perfusion during exercise D. The increase in cerebral blood flow during hypercapnia 8

9 E. None of the above The venous system can act as a reservoir for peripheral blood chiefly because of the: 124 A. low compliance of the venous wall B. absence of smooth muscle fibres in the venous wall C. superficial location of the veins D. large volume capacity of the venous system E. low oxygen saturation in the venous system The greatest percentage of blood volume is found in the: A. heart B. aorta C. distributing arteries and arterioles D. capillaries E. venules and veins 125 Correct statements about the increase in pulmonary blood flow during vigorous exercise include which of the following: 131 A. The percentage of increase in flow is greater in the bases of the lungs than the apices B. The increase in flow is caused by a greater-than-fivefold increase in pulmonary arterial pressure C. The increase in pulmonary blood flow is less than the increase in systemic D. blood flow The increase in pulmonary blood flow is accomodated by dilation of pulmonary arterioles and capillaries E. The increase in pulmonary blood flow is caused by sympathetic nerve stimulation of the pulmonary vasculature In which of the following organs will the rate of blood flow change the LEAST during exercise? 138 A. Skin B. Brain C. Intestine D. Heart E. Kidney In general, the percentage of cardiac output flowing to a particular organ is related to the metabolic activity of that organ in comparison with the other organs of the body. This relationship is true for all the following EXCEPT the: 139 A. B. C. o brain heart skeletal musculature intestine 9

10 E. kidney Use the diagram below to match each shift in cardiac output and central venous pressure with the most likely cause t Cardiac Output 2 Central Venous Pressure A. An increase in contractility B. An increase in blood volume C. An increase in venous compliance D. An increase in total peripheral resistance E. An increase in heart rate A shift in cardiac output and central venous pressure from point 1 to point A shift in cardiac output and central venous pressure from point 1 to point The basic respiratory rhythm is generated by the : 204 A. apneustic centre B. nucleus parabrachialis C. dorsal medulla D. pneumotaxic centre E. cerebrum At the end of quiet inspiration, intraalveolar pressure is normally: 205 A. -40 cm H20 B. -4 cm H20 C. 0 cm H20 D. +4 cm H20 E. +40 cm H20 10

11 The diagram below represents a spirometry tracing illustrating the changes in lung volume that occurred when a subject inhaled maximally and then rapidly exhaled as much gas as possible Volume (Litres) 2 11

12 o Time (Seconds) If the patient's total lung capacity is 6 L, what is the functional residual capacity? 206 A. 1L B. 2 L C. 3 L D. 4 L E. 5 L What is the FEV 1? 207 A. 1.5 L B. 2.5 L C. 3.5 L D. 4.5 L E. 5.5 L What is the inspiratory capacity? 208 A. 1.0 L B. 1.5 L C. 2.0 L D. 2.5 L E. 3.0 L A man ascends to an altitude at which the atmospheric pressure is 400 mmhg. If he reduces his PA C02 to 30 mmhg by hyperventilating, his PA 02 will be closest to: 209 A. 95 mmhg B. 75 mmhg C. 55 mmhg D. 45 mmhg E. 35 mmhg Which of the following lung volumes will change by the greatest amount when a normal person moves from a standing to a supine position? 211 A. Functional residual capacity B. Residual volume C. Total lung capacity D. Vital capacity E. Tidal volume 12