238 Sample Questions

The Heart

1 through 5 apply to the following diagram of the Cardiac Conduction System:

1. The structure which produces a .1 sec. delay in the conduction of the impulse:

(A) 1, (B) 2, (C) 3, (D) 4, (E) 6

2. A bundle block can occur from damage to:

(A) 1 and 2, (B) 3, 4 or 5, (C) 6.

3. An absent P wave would result from damage to:

(A) 1 and 2, (B) 3 and 4, (C) 3, 4, and 5, (D) 6.

4. The fastest myogenic autorhythmic cells are found in: (A) 1, (B) 2, (C) 3, (D) 4.

5. Depolarization in 3, 4, and 5 is seen as part of the:

(A) P wave, (B) QRS complex, (C) T wave.

6. A decrease in which of the following will reduce cardiac output.

(A) systemic venous return, (B) preload,

(C) afterload, (D) peripheral resistance,

(E) Both A and B, (F) Both A and C.

7. Which of the following signals the end of the isovolumetric contraction phase:

(A) semilunar valves open, (B) blood enters the arteries, (C) atrioventricular valves close,

(D) all of the above, (E) A and B only, (F) A and C only.

8. Stretching of pressoreceptors in the right atrium results in reflex as a result of the Bainbridge Reflex.

(A) increase in cardiac output of the ventricles,

(B) decrease in cardiac output of the ventricles.

9. Which ion gates remain open to prolong the depolarization in contractile myocardial cells?

(A) fast Ca⁺² channels, (B) slow Ca⁺² channels, (C) leaky Na⁺ channels (D) K⁺ channels

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10 through 14 apply to the heart diagram at left:

10. The AV node is located in:

(A) 4, (B) 7, (C) 9, (D) 12.

11. The isovolumetric contra

ction phase begins when the ____ valves close.

(A) 5 and 10, (B) 13 and 14, (C) 10 and 13, (D) 5 and 14.

12. Receptors in the baroreceptor reflex are located in:

(A) 1, (B) 2, (C) 3, (D) 8.

13. Stretch receptors in this chamber initiate the “Right Heart Reflex”. (A) 4, (B) 7, (C) 9, (D) 12.

14. The valves which open at the end of the isovolumetric relaxation phase:

(A) 5 and 10, (B) 13 and 14, (C) 10 and 13, (D) 5 and 14

15 through 20 Apply to the diagram at left.

15. The dicrotic notch is occurs at:

(A) 1, (B) 4, (C) 5, (D) 6.

16. The atrioventricular valve opens at:

A) 1, (B) 4, (C) 5, (D) 6.

17. The EDV is seen at:

(A) 2, (B) 4, (C) 6.

18. The aortic semilunar valve opens at:

(A) 1, (B) 4, (C) 5, (D) 6.

19. The isovolumetric contraction phase ends at:

(A) 1, (B) 4, (C) 5, (D) 6.

20. The ESV is seen at:

(A) 2, (B) 4, (C) 6.

21. After passive filling during the quiescent period, the last 30% of blood volume is pushed into the ventricles by

(A) ventricular diastole, (B) atrial diastole, (C) ventricular systole, (D) atrial systole.

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22. When atrial tachycardia occurs the ventricular rate is limited by:

(A) the rate of the AV node, (B) the rate of the SA node, (C) the threshold of the contractile cells,

(D) the refractory period of the ventricular contractile cells,

23. The effect of sympathetic stimulation of the heart includes:

(A) reduced threshold of the myogenic cells, (B) increased threshold of the myogenic cells,

(C) increased force of the contractile cells, (D) both A and C, (E) both B and C.

24. In the ECG shown below which of the following abnormal conditions is observed in the tracing?

(A) the SA node is not firing, (B) the atria are not contracting, (C) the ventricles are contracting.

(D) partial bundle block is seen.

25. The acting pacemaker for the heart seen in the above ECG is the:

(A) SA node, (B) AV node, (C) Purkinje fibers, (D) ligamentum arteriosum.