Cardiovascular Physiology - REVIEW QUESTIONS

Provided by Dr. Robert Lust


Correct Answer:
1. Which of the following statements about the heart is false?

a. Contraction is initiated by a nerve impulse
b. Impulses are conducted from one muscle cell to the next
c. The heart contains a number of cells with an unstable membrane potential
d. The heart contains a number of cells with a stable membrane potential
e. The ventricles are inexcitable for most of the contraction period


Correct Answer:
2. The sinoatrial node is the pacemaker for the heart because the SA node
a. is the most richly enervated structure in the heart
b. is the only structure in the heart capable of generating action potentials
c. has the highest rate of automatic discharge
d. has the most stable transmembrane potential
e. is the cardiac cell least sensitive to catecholamines


Correct Answer:
3. An independence of the P waves and the QRS complexes of the ECG indicates
a. an early repolarization of ventricular fibers
b. a failure of the AV node to conduct
c. a depression of the sinoatrial node
d. slowing of conduction at the atrioventricular node
e. a conduction block in the left bundle branch


Correct Answer:
4. If the end-diastolic ventricular volumes are increased (within physiologic limits)
a. the stroke volume would be increased
b. cardiac output would be decreased
c. venous pressure would be decreased
d. the force of cardiac contraction would be decreased
e. the output of the left ventricle would exceed the output of the left ventricle


Correct Answer:
5. One of the major factors that controls the force of heart contraction is the
a. initial length (preload) of cardiac muscle fibers
b. number of intercalated disks in the cardiac muscle fibers
c. number of gap junctions between cardiac muscle fibers
d. degree of depolarization in the SA node
e. length of the His bundle


Correct Answer:
6. You are watching an ill-tempered child that threatens to hold her breath until her wishes are fulfilled. You say "go ahead" whereupon the child takes a deep breath, holds it, and stares back at you defiantly. The child is incredibly willful, and to your alarm, she passes out in front of you. You rush to the child and discover that
a. her heart rate is low and her pulses are weak, from lack of oxygen
b. her heart rate is fast and her pulses are bounding, from baroreceptor-mediated sympathetic activation
c. her heart rate is normal because the baroreceptors kept her blood pressure up the whole time
d. none of the above


Correct Answer:
7. Positive inotropism refers to
a. decreased stroke volume
b. movement of blood elements related to a change in chemical gradient
c. repolarization of the SA node
d. increased contractility of the heart
e. decreased end-diastolic volume


Correct Answer:
8. Increased pressure within the carotid sinus causes all of the following except
a. a decrease in sympathetic tone to arterioles
b. a decrease in aortic pressure
c. reflex bradycardia
d. vasodilatation of arterioles
e. atrial tachycardia


Correct Answer:
9. The effect of parasympathetic nervous stimulation on the heart is
a. slowing of the heart
b. increased activity of the SA node
c. increased activity of the AV node
d. increased force of contraction
e. all of the above


Correct Answer:
10. The P wave of a normal EKG is associated with
a. the dicrotic notch
b. an increase in atrial pressure
c. atrial contraction
d. ventricular contraction
e. none of the above


Correct Answer:
11. Which of the following mechanisms is most important for maintaining an increased blood flow to skeletal muscle during exercise?
a. An increase in aortic pressure
b. An increase in a-mediated adrenergic impulses
c. An increase in b-mediated adrenergic impulses
d. A vasoconstriction in the splanchnic and renal areas
e. A local vasodilatation secondary to the effect of local metabolites


Correct Answer:
12. Which of the following is most important to blood flow regulation at the local level?
a. Vessel-tissue transmural pressure difference
b. Metabolic activity of the organ or tissue
c. Local neurotransmitters
d. Circulating neurotransmitters
e. Cardiac output


Correct Answer:
13. Which of the following events is represented on the EKG?
a. SA node depolarization
b. AV node depolarization
c. His Bundle depolarization
d. Depolarization of Bachmann's Bundle
e. Atrial muscle depolarization


Correct Answer:
14. A patient with coronary artery disease undergoes coronary arteriography, which reveals an obstruction producing a 50% decrease in the luminal diameter of the left anterior descending coronary artery. If the perfusion is normally 80 mm Hg, what would the new perfusion pressure be, if flow beyond the obstruction was maintained at normal levels?
a. 40 mm Hg
b. 80 mm Hg
c. 120 mm Hg
d. 160 mm Hg
e. 1,280 mm Hg


Correct Answer:
15. A decrease in heart rate, with stroke volume and peripheral resistance held constant, will cause a decrease in all of the following, except
a. arterial diastolic pressure
b. arterial systolic pressure
c. cardiac output
d. arterial pulse pressure
e. mean arterial pressure


Correct Answer:
16. An EKG is recorded with displays no P waves, but a normal appearing QRS and T wave. The pacemaker most likely is located in the
a. SA node
b. AV node
c. His bundle
d. Purkinje system
e. ventricular muscle


Correct Answer:
17. Which of the following best describes conditions consistent with increased contractility?
a. Increased cardiac output for a given end-systolic volume
b. Increased cardiac output for a given end-diastolic volume
c. Decreased cardiac output for a given end-systolic volume
d. Decreased cardiac output for a given end-diastolic volume
e. The ventricles are inexcitable for most of the contraction period


Correct Answer:
18. The ventricles are depolarized or depolarizing during all of the following EKG waves except
a. QRS complex
b. QT interval
c. ST segment
d. PR interval


Correct Answer:
19. The tendency to form edema will be increased by
a. arteriolar constriction
b. increased venous pressure
c. increased plasma protein concentration
d. dehydration


Correct Answer:
20. Myocardial contractility is best correlated with the intracellular concentration of
a. Na+
b. K+
c. Ca++
d. Cl-
e. Mg++


Correct Answer:
21. Cardiac output of the right heart is what percentage of the left heart?
a. 25%
b. 50%
c. 75%
d. 100%
e. 125%


Correct Answer:
22. The greatest pressure drop in the circulation occurs across the arterioles because
a. they have the greatest surface area
b. they have the greatest cross-sectional area
c. the velocity of blood flow through them is highest
d. the velocity of blood flow through them is lowest
e. they have the greatest resistance


Correct Answer:
23. Pulse pressure is
a. the highest pressure measured in the arteries
b. the lowest pressure measured in the arteries
c. the time averaged pressure in the arteries
d. determined by the stroke volume
e. decreased when arterial resistance decreases


Correct Answer:
24. A person has been hypertensive for years, with a resting blood pressure of 180/120. Compared to a normotensive person with a blood pressure of 120/80, if the blood pressure were increased 10 mm Hg above the mean in both patients, the hypertensive patient would demonstrate
a. increased parasympathetic outflow compared to the normotensive patient
b. increased sympathetic outflow compared to the normotensive patient
c. decreased parasympathetic outflow compared to the normotensive patient
d. no difference in autonomic outflow, compared to the normotensive patient


Correct Answer:
25. During rapid acceleration, as a fighter pilot might experience, the pooling of blood in the extremities will
a. increase cardiac output
b. increase venous return
c. decrease arterial blood pressure
d. decrease venous blood volume


Correct Answer:
26. The reflex organization of the cardiovascular system is designed to principally maintain
a. constant oxygen delivery
b. constant arteriolar resistance
c. constant pressure
d. constant cardiac output


Correct Answer:
27. The physiological function of the relatively slow conduction through the AV node is to allow sufficient time for
a. run-off of blood from the aorta to the arterioles
b. venous return to the atria
c. filing of the ventricles
d. contraction of the ventricles
e. repolarization of the ventricles


The following values were obtained in a normal male patient:


heart rate   70 beats/min
arterial [O2]   0.24 ml O2/min
venous [O2]   0.16 ml O2/min
whole body O2 consumption     500 ml/min
pulmonary diastolic pressure   15 mm Hg
pulmonary systolic pressure   25 mm Hg
wedge pressure   5 mm Hg

Use the above data for questions 28, 29 and 30.



Correct Answer:
28. What is the cardiac output?
a. 1.65 L/min
b. 4.55 L/min
c. 5.00 L/min
d. 6.25 L/min
e. 8.00 L/min


Correct Answer:
29. The stroke volume is closest to
a. 75 ml
b. 80 ml
c. 85 ml
d. 90 ml
e. 95 ml


Correct Answer:
30. The pulmonary vascular resistance is closest to
a. 1.5 resistance units (mm Hg/L/min)
b. 2.0 resistance units (mm Hg/L/min)
c. 2.5 resistance units (mm Hg/L/min)
d. 3.0 resistance units (mm Hg/L/min)
e. 3.5 resistance units (mm Hg/L/min)



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