Chapter 4 Blood circulation

一、名词解释

1.Blood circulation:
circulation system is made up of the heart and vessels in which blood is flowing in certain direction ,going round and begin again.

二、选择题
Instructions:
Select the single best answer to the numbered question.

1.Indicate whether the following statement is true or false.
Calcium release from the SR contributes more to cardiac contraction than inflow of Ca++ across the sarcolemma.
A. True
B. False
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2.Calcium removal from the cytoplasm after contraction of the myocardium is:
A. Dependent on the T-type calcium channel
B. Regulated by phospholamban
C. Augmented by the dihydropyridine receptor
D. b & c
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3.Indicate whether the following statement is true or false.
The Frank-Starling Relationship partially explains how cardiac output can be stabilized in a patient after a modest myocardial infarction.
A. True
B. False
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4.Indicate whether the following statement is true or false.
Ventricular filling starts during isometric relaxation.
A. True
B. False
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5.Which of the following factors increase preload? A. Increased blood volume
B. Horizontal posture or negative intrapleural pressure
C. Increased sympathetic tone to veins
D. Skeletal muscle muscular activity
E. all of the above
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6.A reduction in arterial compliance results in:
A. a rise in systolic arterial pressure but a reduction in mean arterial pressure.
B. a rise in systolic and in mean arterial pressure.
C. a rise in systolic but no significant change in mean arterial pressure.
D. a rise in systolic and an even greater rise in diastolic arterial pressure.
E. a fall in systolic but a rise in diastolic arterial pressure.
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7.Which is increased by an increase in total peripheral resistance in an old arteriosclerotic individual:
A. Mean arterial pressure only
B. Pulse pressure only
C. Both of the above
D. Neither of the above
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8.Which is/are increased by a two-fold increase in heart rate simultaneous with a 25% reduction in stroke volume?
A. Mean arterial pressure only
B. Pulse pressure only
C. Both of the above
D. Neither of the above
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9.Increases in arterial capacitance and stroke volume will affect the pulse pressure in opposite directions:
A. True
B. False
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10.A sudden rise in cardiac output would elevate the mean arterial pressure of a person with reduced arterial capacitance more rapidly than it would in a normal person.
A. True
B. False
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11.The venous side of the circulation is characterized by
A. low pressure
B. low resistance to flow.
C. large volume capacity.
D. rich sympathetic and parasympathetic innervation
E. all of the above except D.
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12.In general, it can be said that:
A. the volume capacity of the aorta is high because of its great distensibility.
B. blood volume capacity is highest at the veins, cross sectional area is greatest at the capillaries, and resistance to flow is greatest at the arterioles.
C. blood velocity is similar in all parts of the bed.
D. blood pressure drops from aorta to capillaries, then rises at the level of the venules.
E. All of the above except A.
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13.The arterial side of the circulation is characterized by
A. turbulent blood flow.
B. high pressure.
C. high resistance to flow.
D. small volume capacity.
E. All of the above except A.
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14.The following is/are correct regarding the structure and composition of the vascular bed:
A. aortic capacity is highest because of the large concentration of elastin.
B. blood volume is greatest in the veins, cross sectional area is greatest at the capillaries, and resistance to flow is greatest at the arterioles.
C. blood velocity decreases in the smaller vessels.
D. blood pressure drops from aorta to capillaries, then rises at the level of the venules.
E. B. and C.
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15.The pressure pulse in the root of the aorta is:
A. narrower than the peripheral pulse.
B. characterized by a more pronounced dicrotic notch than would be found in the peripheral vessels.
C. identical to the pulse in the periphery.
D. characterized by a lower frequency than the peripheral pulse.
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16.Mean pressure is approximately equal to:
A. systolic pressure - diastolic pressure
B. systolic pressure + diastolic pressure
C. diastolic pressure + 1/3 systolic pressure
D. 1/3 (systolic pressure - diastolic pressure)
E. none of these
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17.The total resistance through a parallel set of 3 tubes, of resistance 5, 10, and 20 units, respectively is:
A. 0.35 units
B. 2.9 units
C. 3.5 units
D. 35 units
E. 29 units
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18.If you measure the change in pressure in a subject's scalp and in her ankle during the time that she stands up:
A. the arterial pressure in the ankle, would increase more than the venous pressure.
B. due to the cardiac acceleration associated with standing, the measured pressures would rise in both the scalp and the ankle
C. the driving pressure across the leg and the head would increase by the same amount
D. the flow through the artery would increase by more than the flow through the vein because the blood flows down hill in the artery.
E. none of these
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19.Constriction of vessel "C" would increase the filtration of fluid from vessels B1 through B4.
A. True
B. False
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20.Constriction of vessel"A" would have the same effect on total flow through this network as constriction of vessel "C", but would have the opposite effect on filtration from the B vessels.
A. True
B. False
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21.Assumming that all of the "B" vessels below are identical, removal of one of them would be expected to:
A. increase the flow through the network by 33%
B. increase the network resistance by 33%
C. lower the filtration coefficient of the network
D. A and B
E. B and C
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22.When linear velocity of flow in a blood vessel is 100 cm/sec and the volume flow is 200 ml/sec , the cross-sectional area is:
A. 300 cm2
B. 100 cm2
C. 0.5 cm2
D. 2.0 cm2
E. none of these
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23.Select the single best answer to the numbered question.
Given laminar flow of a Newtonian fluid through a cylindrical tube with a fixed driving pressure, if the radius is doubled, flow will:
A. double.
B. remain unchanged.
C. quadruple
D. increase 16-fold.
E. increase 8-fold.
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24.Red blood cells have a relatively small effect on the viscosity of blood in arterioles due to their biconcave disc shape.
A. True
B. False
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25.The total force exerted on the semilunar valves by the pressure of the blood would be doubled if the diameter of the valve were doubled.
A. True
B. False
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26.The driving pressure for a given segment of the circulation is the difference between the input pressure and output pressure to the segment.
A. True
B. False
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27.Blood is thicker than water mainly because of the semi gel nature of the plasma proteins in the body.
A. True
B. False
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28.The velocity of the red cells is usually faster than the velocity of the plasma in the microvessels.
A. True
B. False
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29.If a Newtonian fluid is flowing through a constriction in a circular pipe, which of the following is true?
A. the velocity of the fluid increases as the fluid exits the constriction.
B. the pressure measured by a catheter inserted into the lumen at the constriction would be lower than the pressure measured at the entrance to the constriciton.
C. the velocity through the constriction would vary with the 4th power of the radius of the tube.
D. the total energy of the fluid would increase as the fluid accelerates through the constriction.
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30.If the cardiac output is 6L/min and the arterial pressure is 120 mm Hg, then the capillary pressure must be two millimeters of mercury.
A. True
B. False
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31.Two vessels with equal resistances are connected in series, and the inflow and outflow pressures are fixed. If the resistances of both vessels are doubled, the pressure at a point midway between them would be doubled.
A. True
B. False
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32.Which of the following are true about turbulence?
A. It is less likely to occur at a low flow than at a high flow.
B. For a given flow, turbulence would be more likely to occur in a large vessel than in a small vessel.
C. Turbulence is more likely to occur with a high viscosity fluid than with a low viscosity fluid.
D. Turbulence is noiser than laminar flow.
E. A, and D
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33.In the figure below, which of the curves would likely be the correct description of a distensible vessel?
A. picture
B. picture
C. picture
D. picture
E. picture
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34Shear rate can affect the viscosity of the blood.
A. True
B. False
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35.Examine the drawing below, and choose the correct answer regarding pressures that might be measured in the tube (assume that there are no frictional losses along the length of the tube).
A. P1 < P2
B. P1 > P2
C. P1 = P2
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36.Examine the figure below and answer the questions regarding the pressures.
A. P2 > P3
B. P3 > P2
C. P2 = P3
D. can't say
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37.The shear stress in an artery is greater next to the the wall than at the center of the vessel.
A. True
B. False
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38.Which one of the following statements is true:
A. The higher the molecular weight of a substance the more readily it diffuses across the capillary.
B. Capillary surface area does not influence the amount of substance which diffuses down a concentration gradient.
C. For a given molecular size, lipid insoluble substances diffuse more readily than lipid soluble substances.
D. The transport of small solutes across the capillary wall cannot be described in terms of physical laws.
E. None are true.
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39.Under physiological conditions capillary exchange is controlled primarily by:
A. altered capillary permeability.
B. altered plasma oncotic pressure.
C. altered vascular smooth muscle contraction.
D. altered tissue hydrostatic pressure.
E. altered lymphatic drainage.
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40Given that: 1 = tissue oncotic pressure, 2 = plasma oncotic pressure, 3 = plasma hydrostatic pressure, 4 = tissue hydrostatic pressure, the best statement for the net driving force for capillary filtration is (Hint: think about the forces involved):
A. (3-2) - (4-1)
B. (4-2) - (3-1)
C. (3-1) - (4-2)
D. (2-3) - (1-4)
E. none of the above.
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41The conditions in the blood capillaries are ideal for diffusional exchange because:
A. intracapillary pressure is higher than arteriolar pressure.
B. the small diameter of capillaries permits red cell skimming.
C. the ratio of capillary surface/capillary volume is largest and blood velocity is minimum.
D. of the low capillary flow resistance due to their small total cross- sectional area.
E. pinocytosis is minimal in endothelial cells.
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42.Which one of the following would not be expected to influence lymph flow:
A. Muscular activity.
B. Starvation.
C. A similar increase in precapillary and postcapillary resistance.
D. Stimulation of the sympathetic vasoconstrictor nerves.
E. An infusion of isotonic saline.
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43.In which one of the following pairs of words are the pairs least related:
A. Protein - Van't Hoffs Law.
B. Ultrafiltration - Starling.
C. Diffusion - Fick's Law.
D. Autoregulation - myogenic.
E. Plasma protein osmotic pressure - solute diffusion.
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44.The wall tension in an arteriole 50 mm in diameter with an intraluminal pressure of 80 mmHg is _____ times that of a 25 mm vessel with similar intraluminal pressure:
A. two
B. one half
C. four
D. one fourth
E. 16
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45.Select the single best answer to the numbered question.
Changes in _____ are responsible for the fact that fluid is normally filtered at the arterial end of the capillaries and reabsorbed at the venous end.
A. tissue hydrostatic pressure
B. plasma oncotic pressure
C. diffusion coefficient
D. capillary surface area
E. plasma hydrostatic pressure.
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46.Capillary diffusion capacity is controlled mainly by opening and closing the space between endothelial cells.
A. true
B. false
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47One way of decreasing the resistance of the arterioles with a vasoactive agent would be to decrease the number of arterioles.
A. true
B. false
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48.Lipid solubility and size are more important than charge in the determination of the way in which a molecule will traverse the capillary wall.
A. true
B. false
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49.The major function of the metarterioles is to shunt blood from the arterioles to the venules.
A. true
B. false
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50.Outward capillary filtration is enhanced by:
A. increased plasma oncotic pressure.
B. arteriolar constriction.
C. hypotension.
D. increased venous pressure.
E. increased lymphatic pressure.
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51.The processes of capillary exchanges are best characterized by which of the following statements?
A. The capillary endothelium is permeable to water and electrolytes and impermeable to protein.
B. The rate of diffusion of a solute across the capillary wall is defined by Van't Hoffs law.
C. The capillary pores occupy a large percentage of the total capillary surface area.
D. The rate of diffusion of a solute is directly related to its concentration gradient but indirectly related to its free diffusion coefficient.
E. None are true.
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52.Lymph flow decreases with:
A. Exercise.
B. Hemorrhage.
C. Protein leakage from capillaries
D. Increased venous pressure.
E. Increased arterial pressure.
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53.If the net transmural pressure is 40 mm Hg and flow through the capillary walls is 0.2 ml/min/100g of tissue, the capillary filtration coefficient is:
A. 200
B. 8.0
C. 0.008
D. 0.005
E. 0.002
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54.Arterioles are the main site of vascular resistance to flow because:
A. the effect of their small radius on individual resistances is not compensated by their large number and parallel arrangement.
B. the smooth muscle in the media has a high tone susceptible to modulation by sympathetic nerves.
C. in tubes of their size, the apparent blood viscosity is highest.
D. the ratio of medial thickness to lumenal diameter is very large.
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55.The largest fraction of total blood volume is found:
A. in the aorta
B. between the aorta and capillaries.
C. in small and large veins.
D. in the capillaries
E. in the vena cava
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56.Under physiological conditions, capillary exchange is regulated primarily by:
A. altering capillary permeability.
B. altering plasma oncotic pressure.
C. altering vascular smooth muscle contraction.
C. D altering lymphatic drainage.
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57.Which of the following is not true regarding fluid filtration?
A. The rate of fluid filtration is increased by an increase in tissue oncotic pressure.
B. The rate of fluid filtration is increased during starvation.
C. Most glucose is carried to the tissues in the filtered fluid.
D. Fluid filtration is increased by opening new capillaries.
E. None of these.
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58.Small vessels can sustain large intraluminal pressures because they are supported by the parenchymal cells and thus do not require the connective tissue of the larger elastic arteries.
A. True
B. False
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59.The small amount of protein which leaks from the capillaries is returned to the circulation mainly by pinocytotic transport of the protein across the capillary endothelium.
A. True
B. False
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60.Glucose transport to cells is carried out primarily by filtration of fluid and cotransport of the dissolved glucose through the capillary endothelium.
A. True
B. False
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61.Albumin is about the largest lipid insoluble molecule which will diffuse across the endothelium.
A. True
B. False
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62.Which one of the following statements characterizes the role of the medulla oblongata in the regulation of the heart and blood vessels?
A. It contains a vasomotor center in which some but not all of the descending neurons affecting the control of blood vessels synapse.
B. It contains a cardioinhibitory center which unlike the vasomotor center is little influenced by impulses from carotid baroreceptor.
C. Both statements above are correct.
D. None is correct.
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63.The vasoconstrictor center:
A. is located in the medulla and is tonically active
B. its activity is modulated by the baroreceptors and hypothalmic centers
C. its activity is depressed by lowering the blood pressure in the carotids.
D. its activity is enhanced by carotid chemoreceptor firing and the vasomotor center itself is most sensitive to changes in PCO2 and PO2
E. all of the above except C.
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64.With hemorrhage:
A. pulse pressure decreases.
B. hematocrit ratio increases
C. stroke volume and heart rate increase.
D. number of impulses traveling in the sinus nerves increases.
E. skin temperature increases.
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65.The vasomotor center is stimulated most effectively by:
A. decreased arterial blood oxygen tension.
B. increased arterial blood hydrogen ion concentraion
C. increased arterial blood adenosine concentration
D. increased arterial blood carbon dioxide tension.
E. increased arterial blood potassium ion concentration.
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66.The skin arteriovenous anastamoses:
A. are insensitive to circulating catecholamines.
B. possess a high degree of basal tone.
C. are more sensitive to neural influences than to metabolic stimuli.
D. are less sensitive to sympathetic stimulation than muscle arterioles.
E. dilate in response to cooling of the hypothalamus.
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67.The segment of the vascular bed responsible for local or intrinsic regulation of blood flow in most tissues is:
A. the distributing arteries.
B. the large veins.
C. the capillaries.
D. the venules.
E. the arterioles.
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68.Neural control of the arterioles in skeletal muscle can produce:
A. dilation only.
B. constriction only.
C. both of the above.
D. neither of the above.
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69.Veins in skeletal muscle respond to:
A. sympathetic neural dilation only.
B. sympathetic neural constriction only.
C. both of the above.
D. neither of the above.
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70.Autoregulation:
A. Accounts for the relative constancy of organ blood flow in the face of changes in perfusion pressure.
B. Can be explained by both metabolic and myogenic mechanisms.
C. Accounts for the increase in the organ blood flow when perfusion pressure increases.
D. Is mediated by sympathetic vasoconstrictor fibers.
E. A and B.
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71.Active or functional hyperemia:
A. Is exemplified by the increase in skeletal muscle blood flow during exercise.
B. Is mediated by a decreased washout of metabolites from the active tissue.
C. Is mediated by stretch of the vascular smooth muscle in the active tissue.
D. Is mediated by an increase in mean arterial pressure.
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72.Concerning the control of the cardiovascular system by the autonomic nervous system, the following are true:
A. Control of the sympathetic neural activity to the arterioles can accomplish either constriction or dilation.
B. The effect of sympathetic nerve activity on organ blood volume is negligible.
C. Increased vagal activity causes a decrease in heart rate and a cholinergically-mediated arteriolar vasodilation.
D. Increased parasympathetic nerve activity decreases flow resistance of skeletal- but not visceral smooth muscle.
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73. Stimulation of either the cardiac beta or the vascular beta receptors will have the same effect on the mean arterial pressure.
A. True
B. False
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74.Norepinephrine and angiotensin ll have the same effect on the arterioles.
A. True
B. False
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75.The arterial baroreceptors:
A. Stop firing action potentials above a mean arterial pressure of about 250 mmHg.
B. Show a firing rate that is independent of the magnitude of the pulse pressure.
C. Exert their primary effect via the medullary vasomotor center.
D. Are located within the lumen of most major arteries in the body.
E. A and C.
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76.The baroreceptor-mediated response to increased mean arterial pressure would include:
A. Decreased sympathetic nerve activity to the heart.
B. Peripheral vasodilation.
C. Increased action potential frequency in the afferent nerves to the medullary cardiovascular center.
D. A. and B.
E. A., B. and C.
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77.Calcium in vascular smooth muscle:
A. comes solely from the extracellular fluid.
B. is elevated by norepinephrine but not by oxygen.
C. modulates tone mainly by altering receptor affinity for ligands
D. modulates tone mainly by altering the interaction between actin and myosin
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78.Tone in vascular smooth muscle:
A. is independent of changes in intracellular calcium.
B. is increased by stretch
C. is independent of sympathetic activity
D. is independent of hormonal activity
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79.Endothelial cell communication with the smooth muscle cells of the vessel wall is:
A. due mainly to diffusion of Ca++ from endothelial cell to smooth muscle cells.
B. based on the formation of EDRF (nitric oxide) which diffuses from the endothelial cell to the VSM.
C. stimulated mainly by neural factors
D. sensitive to the concentration of bradykinin in the vessel lumen EDRF
E. B. and D.
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80.Blushing:
A. results from an increase in the sympathetic neural discharge.
B. is induced by parasympathetic neural activation.
C. derives from neural connections in the cerebral cortex.
D. derives from signals originating in the hypothalamus.
E. none of these.
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81.Which of the following vasodilatory responses is most likely due to the parasympathetic nervous system?
A. salivation
B. erection
C. functional dilation of striated muscle
D. heat hyperemia in the skin
E. A. and B.
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82.The fact that the arterioles are more sensitive to neural discharge than the veins assures an appropriate precapillary to post-capillary resistance ratio.
A. True
B. False
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83.The resistance vessels respond to sympathetic stimulation at a lower frequency than do the capacitance vessels.
A. True
B. False
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84.The tissue pressure hypothesis for intrinsic control of blood flow proposes that elevations of perfusion pressure lead to increases in tissue pressure which cause an increase in filtration and therefore a dilution of the concentration of metabolites in the intersitital fluid.
A. True
B. False
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Answer：1.A 2.B 3.A 4.B 5.E 6.C7.C 8.A 9.A 10.A 11.E12.B 13.E 14.E 15.B 16.E17.B 18.E 19.A 20.A 21.E 22.D 23.D 24.B 25.B 26.A 27.B 28.A 29.B 30.B 31.B 32.E 33.A 34.A 35.A 36.B 37.A 38.E 39.C 40.A 41.C 42.C 43.E 44.A 45.E 46.B 47.B 48.A 49.B 50.D 51.A 52.B 53.D 54.A 55.C 56.C 57.C 58.B 59.B 60.B 61.A 62.A 63.E 64.A 65.D 66.C 67.E 68.C 69.B 70.E 71.A
72.A 73.B 74.A 75.C 76.E 77.D 78.B 79.E 80.C 81.E 82.A 83.B 84.B