CHAPTER 4 CIRCULATION MCQ(Please select the single best answer) A1型题 1.Which of the following normally has the most prominent prepotential? A.Sinoatrial node B.Atrial muscle cells C.Bundle of His D.Purkinje fibers E.Ventricular muscle cells [答案]A 2.In second-degree heart block A.the ventricular rate is lower than the atrial rate B.the ventricular ECG complexes are distorted C.there is a high incidence of ventricular tachycardia D.stroke volume is decreased E.cardiac output is increased [答案]A 3. Carotid sinus massage sometimes stops supraventricular tachycardia because A.it decreases sympathetic discharge to the SA node B.it increases vagal discharge to the Sa node C.it increases vagal discharge to the conducting tissue between the atria and the ventricles
CHAPTER 4 CIRCULATION MCQ(Please select the single best answer) A1 型题 1. Which of the following normally has the most prominent prepotential? A. Sinoatrial node B. Atrial muscle cells C. Bundle of His D. Purkinje fibers E. Ventricular muscle cells [答案] A 2. In second-degree heart block A. the ventricular rate is lower than the atrial rate B. the ventricu1ar ECG complexes are distorted C. there is a high incidence of ventricular tachycardia D. stroke volume is decreased E. cardiac output is increased [答案] A 3. Carotid sinus massage sometimes stops supraventricular tachycardia because A. it decreases sympathetic discharge to the SA node B. it increases vagal discharge to the SA node C. it increases vagal discharge to the conducting tissue between the atria and the ventricles
D.it decreases sympathetic discharge to the conducting tissue between the atria and the ventricles E.it increases the refractory period of the ventricular myocardium [答案]C 4.Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of ventricular muscle fibers? A.Na+channels B.Cl-channels C.Ca2+channels D.K+channels E.HC03-channels [答案]D 5.The second heart sound is caused by A.closure of the aortic and pulmonary valves B.vibrations in the ventricular wall during systole C.ventricular filling D.closure of the mitral and tricuspid valves E.retrograde flow in the vena cava [答案]A 6.The fourth heart sound is caused by A.closure of the aortic and pulmonary valves B.vibrations in the ventricular wall during systole C.ventricular filling D.closure of the mitral and tricuspid valves
D. it decreases sympathetic discharge to the conducting tissue between the atria and the ventricles E. it increases the refractory period of the ventricular myocardium [答案] C 4. Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of ventricular muscle fibers? A. Na+ channels B. Cl- channels C. Ca2+ channels D. K+ channels E. HCO3- channels [答案] D 5. The second heart sound is caused by A. closure of the aortic and pulmonary valves B. vibrations in the ventricular wall during systole C. ventricular filling D. closure of the mitral and tricuspid valves E. retrograde flow in the vena cava [答案] A 6. The fourth heart sound is caused by A. closure of the aortic and pulmonary valves B. vibrations in the ventricular wall during systole C. ventricular filling D. closure of the mitral and tricuspid valves
E.retrograde flow in the vena cava [答案]C 7.The dicrotic notch on the aortic pressure curve is caused by A.closure of the mitral valve B.closure of the tricuspid valve C.closure of the aortic valve D.closure of the pulmonary valve E.rapid filling of the left ventricle [答案]C 8.During exercise,a man consumes 1.8 L of oxygen per minute.His arterial 02 content is 190 mL/L,and the 02 content of his mixed venous blood is 134 mL/L. His cardiac output is approximately A.3.2 L/min B.16 L/min C.32 L/min D.54 L/min E.160 mL/min [答案]C 9.The work performed by the left ventricle is substantially greater than that performed by the right ventricle,because in the left ventricle A.the contraction is slower B.the wall is thicker C.the stroke volume is greater D.the preload is greater
E. retrograde flow in the vena cava [答案] C 7. The dicrotic notch on the aortic pressure curve is caused by A. closure of the mitral valve B. closure of the tricuspid valve C. closure of the aortic valve D. closure of the pulmonary valve E. rapid filling of the left ventricle [答案] C 8. During exercise, a man consumes l.8 L of oxygen per minute. His arterial O2 content is 190 mL/L, and the O2 content of his mixed venous blood is l34 mL/L. His cardiac output is approximately A. 3.2 L/min B. l6 L/min C. 32 L/min D. 54 L/min E. 160 mL/min [答案] C 9. The work performed by the left ventricle is substantially greater than that performed by the right ventricle, because in the left ventricle A. the contraction is slower B. the wall is thicker C. the stroke volume is greater D. the preload is greater
E.the afterload is greater [答案]E 10. Starling's law of the heart A.does not operate in the failing heart B.does not operate during exercise C.explains the increase in heart rate produced by exercise D.explains the increase in cardiac output that occurs when venous return is increased E.explains the increase in cardiac output when the sympathetic nerves supplying the heart are stimulated [答案]D 11.Lymph flow from the foot is A.increased when an individual rises from the supine to the standing position B.increased by massaging the foot C.increased when capillary permeability is decreased D.decreased when the valves of the leg veins are incompetent E.decreased by exercise [答案]B 12.The pressure in a capillary in skeletal muscle is 35 mmHg at the arteriolar end and 14 mm Hg at the venular end.The interstitial pressure is 0 mmHg.The colloid osmotic pressure is 25 mm Hg in the capillary and 1 mm Hg in the interstitium.The net force producing fluid movement across the capillary wall at its arteriolar end is
E. the afterload is greater [答案] E 10. Starling’s law of the heart A. does not operate in the failing heart B. does not operate during exercise C. explains the increase in heart rate produced by exercise D. explains the increase in cardiac output that occurs when venous return is increased E. explains the increase in cardiac output when the sympathetic nerves supplying the heart are stimulated [答案] D 11. Lymph flow from the foot is A. increased when an individual rises from the supine to the standing position B. increased by massaging the foot C. increased when capillary permeability is decreased D. decreased when the valves of the leg veins are incompetent E. decreased by exercise [答案] B 12. The pressure in a capillary in skeletal muscle is 35 mm Hg at the arteriolar end and l4 mm Hg at the venular end. The interstitial pressure is 0 mmHg. The colloid osmotic pressure is 25 mm Hg in the capillary and l mm Hg in the interstitium. The net force producing fluid movement across the capillary wall at its arterio1ar end is
A.3 mm Hg out of the capillary B.3 mm Hg into the capillary C.10 mm Hg out of the capillary D.11 mm Hg out of the capillary E.11 mm Hg into the capillary [答案]D 13.Which of the following does not occur as blood passes through the systemic capillaries? A.Its hematocrit increases B.Its hemoglobin dissociation curve shift to the left C.Its protein content increases D.Its pH decreases E.Its red blood cells increase in size [答案]B 14.The velocity of blood flow A.is higher in the capillaries than the arterioles B.is higher in the veins than in the venules C.is higher in the veins than the arteries D.falls to zero in the descending aorta during diastole E.is reduced in a constricted area of a blood vessel [答案]B 15.When the radius of the resistance vessels is increased,which of the following is increased? A.Systolic blood pressure
A. 3 mm Hg out of the capillary B. 3 mm Hg into the capillary C. 10 mm Hg out of the capillary D. 11 mm Hg out of the capillary E. 11 mm Hg into the capillary [答案] D 13. Which of the following does not occur as blood passes through the systemic capillaries? A. Its hematocrit increases B. Its hemoglobin dissociation curve shift to the left C. Its protein content increases D. Its pH decreases E. Its red blood cells increase in size [答案] B 14. The velocity of blood flow A. is higher in the capillaries than the arterioles B. is higher in the veins than in the venules C. is higher in the veins than the arteries D. falls to zero in the descending aorta during diastole E. is reduced in a constricted area of a blood vessel [答案] B 15. When the radius of the resistance vessels is increased, which of the following is increased? A. Systolic blood pressure
B.Diastolic blood pressure C.Viscosity of the blood D.Hematocrit E.Capillary blood flow [答案]E 16.When the viscosity of the blood is increased,which of the following is increased? A.Mean blood pressure B.Radius of the resistance vessels C.Radius of the capacitance vessels D.Central venous pressure E.Capillary blood flow [答案]A 17.A pharmacologist discovers a drug that simulates the production of VEGF receptors.He is excited because his drug might be of value in the treatment of A.coronary artery disease B.cancer C.diabetes mellitus D.diabetes insipidus E.dysmenorrhea [答案]A 18.Which of the following are incorrectly paired? A.Angiotensin II-converting enzyme:kinin metabolism B.Stimulation of the vagus nerve in the neck:bradycardia
B. Diastolic blood pressure C. Viscosity of the blood D. Hematocrit E. Capillary blood flow [答案] E 16. When the viscosity of the blood is increased, which of the following is increased? A. Mean blood pressure B. Radius of the resistance vessels C. Radius of the capacitance vessels D. Central venous pressure E. Capi1lary blood flow [答案] A 17. A pharmacologist discovers a drug that simulates the production of VEGF receptors. He is excited because his drug might be of value in the treatment of A. coronary artery disease B. cancer C. diabetes mellitus D. diabetes insipidus E. dysmenorrhea [答案] A 18. Which of the following are incorrectly paired? A. Angiotensin II-converting enzyme: kinin metabolism B. Stimulation of the vagus nerve in the neck: bradycardia
C.Prostacyclin:vasodilation D. Increased pressure in the carotid sinuses:decreased sympathetic discharge to arterioles E.Increased H2 in tissues:vasoconstriction in tissues [答案]E 19. When a pheochromocytoma (tumor of the adrenal medulla)suddenly discharges a large amount of epinephrine into the circulation,the patient's heart rate would be expected to A.increase because the increase in blood pressure stimulates the carotid and aortic baroreceptors B.increase because epinephrine has a direct chronotropic effect on the heart C.increase because of increased tonic parasympathetic discharge to the heart D.decrease because the increase in blood pressure stimulates the carotid and aortic chemoreceptors E. decrease because of increased tonic parasympathetic discharge to the heart [答案]B 20. Vasopressin secretion is increased by A.increased pressure in the right ventricle B.decreased pressure in the right ventricle C.increased pressure in the right atrium D.decreased pressure in the right atrium E.increased pressure in the aorta [答案]D
C. Prostacyclin: vasodilation D. Increased pressure in the carotid sinuses: decreased sympathetic discharge to arterioles E. Increased H2 in tissues: vasoconstriction in tissues [答案] E 19. When a pheochromocytoma (tumor of the adrenal medulla) suddenly discharges a large amount of epinephrine into the circulation, the patient’s heart rate would be expected to A. increase because the increase in blood pressure stimulates the carotid and aortic baroreceptors B. increase because epinephrine has a direct chronotropic effect on the heart C. increase because of increased tonic parasympathetic discharge to the heart D. decrease because the increase in blood pressure stimulates the carotid and aortic chemoreceptors E. decrease because of increased tonic parasympathetic discharge to the heart [答案] B 20. Vasopressin secretion is increased by A. increased pressure in the right ventricle B. decreased pressure in the right ventricle C. increased pressure in the right atrium D. decreased pressure in the right atrium E. increased pressure in the aorta [答案] D
21.Catecholamines acting on a-adrenergic receptors A.increase the contractility of cardiac muscle B.increase the rate of discharge of the sinoatrial node C.increase cardiac output D.constrict coronary arteries by a direct action on these blood vessels E.dilate blood vessels in skeletal muscle [答案]D 22. Blood in which of the following vessels normally has the lowest P02? A.Maternal artery B.Maternal uterine vein C.Maternal femoral vein D.Umbilical artery E.Umbilical vein [答案]D 23.The pressure differential between the heart and the aorta is least in the A.left ventricle during systole B.left ventricle during diastole C.right ventricle during systole D.right ventricle during diastole E.left atrium during systole [答案]A 24.Injection of tissue plasminogen activator (t-PA)would probably be most beneficial
21. Catecholamines acting on α-adrenergic receptors A. increase the contractility of cardiac muscle B. increase the rate of discharge of the sinoatrial node C. increase cardiac output D. constrict coronary arteries by a direct action on these blood vessels E. dilate blood vessels in skeletal muscle [答案] D 22. Blood in which of the following vessels normally has the lowest PO2? A. Maternal artery B. Maternal uterine vein C. Maternal femoral vein D. Umbilical artery E. Umbilical vein [答案] D 23. The pressure differential between the heart and the aorta is least in the A. left ventricle during systole B. left ventricle during diastole C. right ventricle during systole D. right ventricle during diastole E. left atrium during systole [答案] A 24. Injection of tissue plasminogen activator (t-PA) would probably be most beneficial
A.after at least 1 year of uncomplicated recovery following occlusion of a coronary artery B.after at least 2 months of rest and recuperation following occlusion of a coronary artery C.during the second week after occlusion of a coronary artery D.during the second day after occlusion of a coronary artery E.during the second hour after occlusion of a coronary artery [答案]E 25. Which of the following organs has the greatest blood flow per 100 g of tissue? A.Brain B.Heart muscle C.Skin D.Liver E.Kidneys [答案]E 26. Which of the following organs has the most permeable capillaries? A.Brain B.Posterior pituitary gland C.Liver D.Small intestine E.Kidneys [答案]C 27.Which of the following does not dilate arterioles in the skin?
A. after at least l year of uncomplicated recovery following occlusion of a coronary artery B. after at least 2 months of rest and recuperation following occlusion of a coronary artery C. during the second week after occlusion of a coronary artery D. during the second day after occlusion of a coronary artery E. during the second hour after occlusion of a coronary artery [答案] E 25. Which of the following organs has the greatest blood flow per l00 g of tissue? A. Brain B. Heart muscle C. Skin D. Liver E. Kidneys [答案] E 26. Which of the following organs has the most permeable capillaries? A. Brain B. Posterior pituitary gland C. Liver D. Small intestine E. Kidneys [答案] C 27. Which of the following does not dilate arterioles in the skin?
A.Increased body temperature B.Epinephrine C.Bradykinin D. Substance P E.Vasopressin [答案]E 28.A baby boy is brought to the hospital because of convulsions.In the course of a workup,his body temperature and plasma glucose are found to be normal,but his cerebrospinal fluid glucose is 12 mg/dL (normal,65 mg/dL).A possible explanation of his condition is A.constitutive activation of GLUT 3 in neurons B.SGLT 1 deficiency in astrocytes C.GLUT 5 deficiency in cerebral capillaries D.GLUT 1 55K deficiency in cerebral capillaries E.GLUT 1 45K deficiency in microglia [答案]D 29.Which of the following is most beneficial when administered in the first 2-3 hours following the onset of an ischemic stroke A.Proinsulin B.Blood transfusion C.Glycine receptor antagonists D.B-Adrenergic blocking drugs E.t-PA [答案] 30.Plasma renin activity is most likely to be lower than normal
A. Increased body temperature B. Epinephrine C. Bradykinin D. Substance P E. Vasopressin [答案] E 28. A baby boy is brought to the hospital because of convulsions. In the course of a workup, his body temperature and plasma glucose are found to be normal, but his cerebrospinal fluid glucose is l2 mg/dL (normal, 65 mg/dL). A possible explanation of his condition is A. constitutive activation of GLUT 3 in neurons B. SGLT l deficiency in astrocytes C. GLUT 5 deficiency in cerebral capillaries D. GLUT l 55K deficiency in cerebral capillaries E. GLUT l 45K deficiency in microglia [答案] D 29. Which of the following is most beneficial when administered in the first 2-3 hours following the onset of an ischemic stroke A. Proinsulin B. Blood transfusion C. Glycine receptor antagonists D. β-Adrenergic blocking drugs E. t-PA [答案] 30. Plasma renin activity is most likely to be lower than normal