a)
b)
c)
d)
PHYSIOLOGY ASSIGNMENT – CVS
Write your computer number, date and course on your cover page
Record the letter that corresponds to the correct answer on your answer sheet
Deadline: Tuesday 08hrs
Submit your answers to the class rep
Question
1. Excitation of baroreceptors in arteries reflexly causes:
a. Arterial pressure to decrease.
b. Peripheral vasoconstriction.
c. Increased cardiac output.
d. Vasovagal syncope.
e. Prolonged P-R interval.
2. Cardiac output is equal to:
a. Stroke volume (SV) X venous return (VR).
b. End diastolic volume (EDV) _end systolic volume (ESV).
c. Stroke volume (SV)X heart rate (HR).
d. 300 ml / min.
e. Cardiac index.
3. The most frequent cause of diminished coronary blood flow is:
a. mitral stenosis.
b. Exercise.
c. Atherosclerosis.
d. Mass sympathetic discharge.
e. Increased venous return.
4. The adhesion of platelets to subendothelial collagen is impaired in the absence of:
A. von Willebrand factor
B. plasmin
C. heparin
D. antithrombin III
5. The heart continues to beat even after all nerves to it are sectioned. This property is called:
A. excitability
B. conductivity
C. automaticity
D. contractility
6. What is the primary ionic basis of the prepotential in the SA node?
A. Ca influx through transient T Ca channels
B. Inwardly directed long-lasting Ca current
C. Outward Na current
D. Potassium efflux through leak channels
7. Normally, the impulse that excites the left ventricular myocardium originates in the:
A. SA node
B. Purkinje system
C. left bundle branch
D. ventricle
8. Conduction speed is slowest in the:
A. SA node
B. atrial pathways
C. bundle of His
D. Purkinje system
E. Ventricular myocardium
9. What is the effect of vagal stimulation on the membrane potential of the SA node?
A. It increases an inward calcium current.
B. It increases the slope of the prepotential.
C. It activates a hyperpolarizing potassium current.
D. It increases intracellular cAMP.
10. Activation of beta-adrenergic receptors in the heart is normally associated with which of the
following?
A. Decrease in the slope of phase 4 depolarization in SA nodal cells.
B. Decrease in conduction speed through AV node.
C. Inhibition of Ca induced Ca release following depolarization in ventricular myocytes.
D. Accelerated sequestration of Ca in the sarcoplasmic reticulum by the Ca-ATPase
E. Reduction in the rate of rise in ventricular pressure during isovolumic contraction
11. Prepotentials are normally absent from:
A. P cells in the SA node
B. AV nodal cells
C. Purkinje fibers
D. working myocardial cells
12. Cardiac muscle cannot be tetanized because of:
A. accommodation
B. its slow rate of repolarization
C. calcium influx during phase II
D. voltage inactivation of Na channels at membrane potentials < 80 mV
13. Intrinsic heart rate is determined by:
A. vagotomy
B. administration of atropine
C. beta-adrenergic receptor blockade
D. IV administration of atropine and atenolol
14. The ability of the AV node to generate its own impulses when the sinus node is “sick” is due to:
A. a constant phase 4 membrane potential
B. slow calcium entry during phase zero
C. spontaneous diastolic depolarization
D. the absence of prepotentials
15. The propagation of repolarization from the ventricular epicardium to endocardium is
represented by the
A. QRS complex
B. QT interval
C. T wave
D TP period
16. T wave inversion occurs when ventricular repolarization occurs from:
A. endocardium to epicardium
B. epicardium to endocardium
C. apex to base of the heart
D. base to apex of the heart
17. Which of the following is the shortest event in a cardiac cycle?
A. QRS interval
B. ST segment
C. ST interval
D. RR interval
18. Electrical activity in which region of the heart does not result in deflections on the surface
electrocardiogram?
A. Atria
B. Bundle of His
C. Free wall of the left ventricle
D. Free wall of the right ventricle
E. Muscular portion of the ventricular septum
19. In sinus rhythm, the last portion of the ventricle to depolarize is:
A. interventricular septum from left to right
B. anteroseptal region of the myocardium
C. most of the myocardium from endocardium to epicardium
D. posterobasal portion of left ventricle and the pulmonary conus
20. The most reliable index of AV nodal delay is:
A. AH interval
B. PA interval
C. PR interval
D. PR segment
21. Hypocalcemia is associated with QT prolongation because:
A. it is invariably associated with bundle branch block
B. it increases ventricular activation time
C. it lengthens the duration of ventricular repolarization
D. it accelerates opening of potassium channels
22. Stimulation of sympathetic nerves to the heart decreases:
A. heart rate
B. force of cardiac contraction
C. speed of conduction
D. refractory period
23. Right axis deviation may occur in:
A. deep inspiration
B. emphysema
C. dextrocardia
D. pulmonary hypertension
24. The ST segment is elevated in acute myocardial infarction because of:
A. flow of current into the infarct during diastole
B. TP segment depression
C. late depolarization of infarct
D. early repolarization of infarct
25. During the cardiac cycle, aortic valve closes at the end of:
A. isovolumetric systole
B. rapid ejection
C. diastasis
D. protodiastole
27. The maximum pressure rise in the ventricle occurs during:
A. ejection
B. isovolumetric contraction
C. protodiastole
D. diastasis
28. Normally, which of the following events in the cardiac cycle occurs at some point between S1
and the following S2?
A. Onset of ventricular diastole
B. Atrial systole
C. Rapid ventricular filling
D. The ‘a’ wave of the JVP
E. The ‘y’ descent in the JVP
29. Comparing left and right atria, the left atrium normally has a taller v wave than the right atrium
because
A. left atrial filling pressure is high
B. pulmonary vessels empty into the left atrium
C. left atrium is more complaint
D. right ventricle is more compliant
30. Which of the following is a low pitched sound heard best in the apex just prior to S1 and is
associated with effective atrial contractions in the setting of diminished ventricular compliance?
A. Pericardial knock
B. Opening snap
C. S3
D. S4
31. In which of the following states is isovolumetric ventricular relaxation abbreviated, assuming that
the prevailing heart rate is identical in each?
A. Aortic regurgitation
B. Mitral regurgitation
C. Mitral stenosis
D. Tricuspid regurgitation
E. Patent ductus arteriosus
32. The most appropriate index of left ventricular afterload is
A. systolic arterial pressure
B. mean arterial pressure
C. systemic vascular resistance
D. aortic valve resistance
E. left ventricular systolic pressure
33. Right ventricular preload typically exceeds left ventricular preload during:
A. deep inspiration
B. deep expiration
C. Valsalva maneuver (done for 15 seconds)
D. quiet standing
34. LV preload is increased by a/an:
A. increase in intrapericardial pressure
B. decrease in left ventricular compliance
C. sympathetic stimulation of veins and the heart
D. inhibition of Na-K ATPase in cardiomyocytes
35. An increase in whole body oxygen demand is met chiefly by:
A. increasing cardiac output
B. increasing oxygen content of arterial blood
C. increasing oxygen extraction from arterial blood
D. increasing blood pressure
36. Windkessel vessels are represented by the:
A. aorta
B. internal jugular v.
C. arterioles
D. muscular arteries
37. At any time, the greatest fraction of blood volume is present in the:
A. heart
B. arteries
C. veins
D. capillaries
38. The term “capacitance vessels” is applied to:
A. pulmonary capillaries
B. thoroughfare channels
C. shunts
D. veins and venules
39. Hydraulic conductivity of capillaries is highest in:
A. glomeruli
B. intestinal villi
C. skin
D. brain
40. What would be the change in blood flow to a tissue if radius of the arterioles in that tissue is
doubled and perfusion pressure is halved?
A. Increase 8 times
B. Increase 16 times
C. Increase 4 times
D. Decreases 4 times
41. The pressure in a blood vessel at which flow ceases is called
A. mean arterial pressure
B. pulse pressure
C. critical closing pressure
D. perfusion pressure
42. Thin walled capillaries do not burst when intracapillary pressure is increased within physiologic
limits because:
A. they lack smooth muscle cells
B. the blood flow rate is less
C. they have a small radius
D. capillary hematocrit is less than whole-body hematocrit.
43. When determining BP with a sphygmomanometer, a spuriously high value (of either SBP or DBP)
may be recorded when:
A. there is an auscultatory gap
B. the cuff is smaller than preferable
C. the person is obese
D. the arm is not placed at the level of the heart
44. Which of the following is usually associated with turbulence in blood flow?
A. Reynolds number less than 2000
B. Decrease in blood flow velocity
C. Decrease in density of blood
D. Increase in diameter of blood vessel
45. Filtration at the arterial end of capillary occurs mainly due to:
A. hydrostatic pressure in capillaries
B. hydrostatic pressure in interstitium
C. oncotic pressure in capillaries
D. oncotic pressure in interstitium
46. Patients with acute cardiac failure may not have edema if:
A. oncotic pressure of plasma proteins is high
B. renal compensation occurs
C. cardiac output is decreased
D. there is a fall in systemic capillary hydrostatic pressure
47. Venous return is transiently increased during:
A. strain phase of Valsalva maneuver
B. positive end-expiratory pressure
C. intravenous bolus of frusemide
D. deep inspiration
48. the most important means of increasing flow to an actively metabolizing tissue is:
A. increasing cardiac output
B. increasing peripheral resistance
C. increasing blood pressure
D. decreasing local vascular resistance
49. Which of the following has a direct vasodilator effect on smooth muscle in arterioles in the
presence of endothelial dysfunction?
A. Acetylcholine
B. Angiotensin II
C. Nitric oxide
D. Norepinephrine
E. Thromboxane A2
50. The most potent vasoconstrictor is:
A. endothelin 1
B. angiotensin II
C. norepinephrine
D. vasopressin
51. On rising from the supine position:
A. central blood volume increases
B. heart rate decreases
C. central venous pressure decreases
D. discharge from arterial baroreceptors decreases
E. stroke volume decreases
52. Loss of 500 ml of blood over 30 minutes will lead to:
A. an increase in HR, fall in BP
B. a fall in BP and HR
C. a prominent increase in HR and BP
D. a slight increase in HR
53. The wheal in the triple response is due to:
A. contraction of precapillary sphincters
B. increased capillary permeability
C. axon reflex
D. decreased absorption of fluid
54. Which of the following physiologic responses has a neural basis?
A. Red reaction
B. White reaction
C. Flare
D. Reactive hyperemia
55. Orthopnea in heart failure occurs when the reservoir function of which of the following is
overwhelmed?
A. Pulmonary veins
B. Pulmonary arteries
C. Right atrium
D. Systemic veins
56. Palpable enlargement of the liver in an individual with heart failure is most closely
related to:
A. a decrease in pulmonary venous pressure
B. an increase in left ventricular compliance
C. an increase in mean arterial pressure
D. an increase in mean right atrial pressure
E. an increase in systemic vascular resistance
57. Plasma level of brain natriuretic peptide is least likely to be elevated in:
A. acute mitral regurgitation
B. cardiac tamponade due to chest trauma
C. heart failure due to dilated cardiomyopathy
D. heart failure due to acute aortic regurgitation
E. heart failure post myocardial infarction
58. A 30-year-old man has an ejection fraction of 0.25 and an end systolic volume of 150 ml. What is
his end diastolic volume?
A) 50 ml
B) 100 ml
C) 125 ml
D) 200 ml
E) 250 ml
59. Which of the following statements about cardiac muscle is most accurate?
A) The T-tubules of cardiac muscle can store much less calcium than T-tubules in skeletal muscle
B) The strength and contraction of cardiac muscle depends on the amount of calcium surrounding
cardiac myocytes
C) In cardiac muscle the initiation of the action potential causes an immediate opening of slow
calcium channels
D) Cardiac muscle repolarization is caused by opening of sodium channels
E) Mucopolysaccharides inside the T-tubules bind chloride ions
60. Which of the following is most likely to cause the heart to go into spastic contraction?
A) Increased body temperature
B) Increased sympathetic activity
C) Decreased extracellular fluid potassium ions
D) Excess extracellular fluid potassium ions
E) Excess extracellular fluid calcium ions
61. Which of the following events occurs at the end of the period of ventricular ejection?
A) A-V valves close
B) Aortic valve opens
C) Aortic valve remains open
D) A-V valves open
E) Pulmonary valve closes
62. Which of the following phases of the cardiac cycle follows immediately after the beginning of the
QRS wave?
A) Isovolumic relaxation
B) Ventricular ejection
C) Atrial systole
D) Diastasis
E) Isovolumic contraction
63. Which of the following events is associated with the first heart sound?
A) Closing of the aortic valve
B) Inrushing of blood into the ventricles during diastole
C) Beginning of diastole
D) Opening of the A-V valves
E) Closing of the A-V valves
64. Which of the following conditions at the A-V node will cause a decrease in heart rate?
A) Increased sodium permeability
B) Decreased acetylcholine levels
C) Increased norepinephrine levels
D) Increased potassium permeability
E) Increased calcium permeability
65. Sympathetic stimulation of the heart
A) Releases acetylcholine at the sympathetic endings
B) Decreases sinus nodal discharge rate
C) Decreases excitability of the heart
D) Releases norepinephrine at the sympathetic endings
E) Decreases cardiac contractility
66. Which of the following structures will have the slowest rate of conduction of the cardiac action
potential?
A) Atrial muscle
B) Anterior internodal pathway
C) A-V bundle fibers
D) Purkinje fibers
E) Ventricular muscle
67. When recording lead I on an EKG, the right arm is the negative electrode, and the positive
electrode
is the
A) left arm
B) left leg
C) right leg
D) left arm + left leg
E) right arm + left leg
68 When recording lead aVL on an EKG, the positive electrode is the
A) left arm
B) left leg
C) right leg
D) left arm + left leg
E) right arm + left leg
69. What is the normal QT interval?
A) 0.03 seconds
B) 0.13 seconds
C) 0.16 seconds
D) 0.20 seconds
E) 0.35 seconds
70. Which of the following conditions will usually result in right axis deviation in an EKG?
A) Systemic hypertension
B) Aortic valve stenosis
C) Aortic valve regurgitation
D) Excess abdominal fat
E) Pulmonary hypertension
71. A 60-year-old woman has lost some ability to perform normal household tasks and is not feeling
well. An EKG shows a QRS complex with a width of 0.20 sec, the T wave is inverted in lead I, and the
R wave has a large negative deflection in lead III. Which of the following is the likely diagnosis?
A) Right ventricular hypertrophy
B) Left bundle branch block
C) Pulmonary valve stenosis
D) Right bundle branch block
E) Left ventricular hypertrophy
72. A 30-year-old man had his EKG measured at his physician’s office, but his records were lost. The
EKG technician remembered that the QRS deflection was large and positive in lead aVF and 0 in lead
I. What is the mean electrical axis in the frontal plane?
A) 90°
B) 60°
C) 0°
D) −60°
E) −90°
73. Which of the following is most likely at the “J point” in an EKG of a patient with a damaged
cardiac muscle?
A) Entire heart is depolarized
B) All the heart is depolarized except for the damaged cardiac muscle
C) About half the heart is depolarized
D) All of the heart is repolarized
E) All of the heart is repolarized except for the damaged cardiac muscle
74. A 50-year-old man has a blood pressure of 140/85 and weighs 200 lb. He reports that he is not
feeling well, his EKG has no P-waves, he has a heart rate of 46, and the QRS complexes occur
regularly.
What is his likely condition?
A) First-degree heart block
B) Second-degree heart block
C) Third-degree heart block
D) Sinoatrial heart block
E) Sinus bradycardia
75. An 80-year-old man had an EKG taken at his local doctor’s office, and the diagnosis was atrial
fibrillation. Which of the following statements are likely conditions in someone with atrial
fibrillation?
A) Ventricular fibrillation normally accompanies atrial fibrillation
B) P waves of the EKG are strong
C) Rate of ventricular contraction is irregular and fast
D) Atrial “a” wave is normal
E) Atria have a smaller volume than normal
76. A 60-year-old woman tires easily. Her EKG shows a QRS complex that is positive in the aVF lead
and negative in standard limb lead I. A likely cause of this condition is which of the following?
A) Chronic systemic hypertension
B) Pulmonary hypertension
C) Aortic valve stenosis
D) Aortic valve regurgitation
77. Circus movements in the ventricle can lead to ventricular fibrillation. Which of the following
conditions in the ventricular muscle will increase the tendency for circus movements?
A) Decreased refractory period
B) Low extracellular potassium concentration
C) Increased refractory period
D) Shorter conduction pathway (decreased ventricular volume)
E) Increase in parasympathetic impulses to the heart
78. A 55-year-old man has been diagnosed with Stokes-Adams syndrome. Two minutes after the
syndrome starts to cause active blockade of the cardiac impulse, which of the following is the
pacemaker of the heart?
A) Sinus node
B) A-V node
C) Purkinje fibers
D) Cardiac septum
E) Left atrium
79. Which part of the ECG corresponds to ventricular repolarization?
A) the P wave
B) the QRS duration
C) the T wave
D) the U wave
E) the PR interval
80. Which of the following normally has a slowly depolarizing “prepotential”?
A) sinoatrial node
B) atrial muscle cells
C) bundle of His
D) Purkinje fibers
E) ventricular muscle cells
81. 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.
82. 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
83. In complete heart block
A) fainting may occur because the atria are unable to pump blood into the ventricles.
B) ventricular fibrillation is common.
C) the atrial rate is lower than the ventricular rate.
D) fainting may occur because of prolonged periods during which the ventricles fail to contract.
84. 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.
85. 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.
86. 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.
87. 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.
88. 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.
89. Which of the following has the highest total cross-sectional area in the body?
A) arteries
B) arterioles
C) capillaries
D) venules
E) veins
90. 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.
91. 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
92. When the viscosity of the blood is increased, which of the fol lowing 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
93. Activation of the baroreceptor reflex
A) is primarily involved in short-term regulation of systemic blood pressure.
B) leads to an increase in heart rate because of inhibition of the vagal cardiac motor neurons.
C) inhibits neurons in the CVLM.
D) excites neurons in the RVLM.
E) all of the above
94. Sympathetic nerve activity would be expected to increase
A) if glutamate receptors were blocked in the NTS.
B) if GABA receptors were blocked in the RVLM.
C) if there was a compression of the RVLM.
D) during hypoxia.
E) for all of the above.
95. Why is the dilator response to injected acetylcholine changed to a constrictor response when the
endothelium is damaged?
A) More Na+ is generated.
B) More bradykinin is generated.
C) The damage lowers the pH of the remaining layers of the artery.
D) The damage augments the production of endothelin by the endothelium.
E) The damage interferes with the production of NO by the endothelium.
96. 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
97. 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.
98. 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
99. Which of the following does not dilate arterioles in the skin?
A) increased body temperature
B) epinephrine
C) bradykinin
D) substance P
E) vasopressin
100. One of the most important feature of the progressive shock is:
a. Initiation of baroreceptor reflex.
b. Progressive cardiac deterioration.
c. Return of blood volume back to normal.
d. Maintenance of arterial pressure and cardiac output.
e. CNS ischemic response.