BY 32 – SPRING 2000

Section 6143

EXAM 3

NAME ___________________________________

Instructions: Record your answers directly on this sheet by circling the correct response. For each question, choose the single best response.

1. The amount of blood pumped by the heart each minute is referred to as the: (C)

a. stroke volume.

b. residual volume.

c. cardiac output.

d. total peripheral resistance.

2. Venous blood returning from the pulmonary circulation drains first to which heart chamber? (C)

a. Right atrium

b. Right ventricle

c. Left atrium

d. Left ventricle

3. The heart is located within a space of the thoracic cavity called the: (D)

a. pericardial cavity.

b. coronary sinus.

c. pleural cavity.

d. mediastinum.

4. Which of the following structures consists of a single layer of mesothelial cells? (C)

a. The endocardium

b. The myocardium

c. The serous pericardium

d. The fibrous pericardium

5. The layer of the heart which in some areas contain substantial amounts of adipose tissue is called the: (C)

a. fibrous pericardium.

b. myocardium.

c. epicardium.

d. endocardium.

6. The portion of the atria that resemble the external ears of dogs are called: (B)

a. trabeculae carnae.

b. auricles.

c. pectinate muscles.

d. chordae tendinea.

7. The coronary sinus lies in a groove of the heart called the: (A)

a. atrioventricular sulcus.

b. anterior interventricular sulcus.

c. posterior interventricular sulcus.

d. interventricular septum.

8. Because of its number of cusps, the left atrioventricular valve is sometimes called the: (A)

a. bicuspid valve.

b. tricuspid valve.

c. aortic semilunar valve.

d. pulmonary semilunar valve.

9. During ventricular systole, eversion of the atrioventricular valves is prevented by contraction of: (C)

a. the pectinate muscles.

b. the trabeculae carnae.

c. the papillary muscles.

d. the interventricular septum.

10. The fibrous skeleton of the heart consists of the roots of the great vessels, the membranous interventricular septum and the: (C)

a. bundle of His.

b. atrioventricular sulcus.

c. annulus fibrosus.

d. coronary sinus.

11. Blood flow during the coronary circulation virtually ceases during which phase of the cardiac cycle? (D)

a. Isovolumetric relaxation

b. Rapid ventricular filling

c. Diastasis

d. Ventricular systole

12. Action potentials pass from cell to cell in the heart via which of the following structures? (D)

a. T tubules

b. Cross bridges

c. Desmosomes

d. Gap junctions

13. Within an elastic artery, the portion that contains the tissue type endothelium is called the: (A)

a. tunica intima.

b. tunica media.

c. tunica adventitia.

d. internal elastic lamina.

14. Within a capillary bed, constriction of the precapillary sphincter shunts blood into: (B)

a. the capillaries.

b. the metarteriole.

c. the interstitial space.

d. the arterioles.

15. Of the various types of capillaries, those with the highest permeability are the: (D)

a. continuous capillaries in the brain.

b. continuous capillaries in the heart.

c. fenestrated capillaries.

d. discontinuous capillaries.

16. The cell type found just outside of the basement membrane of capillaries and postcapillary venules is called the: (D)

a. endothelial cell.

b. smooth muscle cell.

c. fibroblast.

d. pericyte.

17. Within the systemic circulation, most blood volume is found within: (D)

a. the heart.

b. the arteries.

c. the capillaries.

d. the veins.

18. The resting potential of a typical contractile cell of the heart is typically on the order of –90 mV, which is attributable to relatively high permeability of the cell membrane to which of the following ions? (B)

a. Na⁺

b. K⁺

c. Ca²⁺

d. Cl^-

19. When a contractile cell is brought to threshold by excitation from a neighboring cell, the rapid depolarization of the membrane is attributable to an increase in permeability of which of the following ions? (A)

a. Na⁺

b. K⁺

c. Ca²⁺

d. Cl^-

20. Which of the following cell types possess pacemaker potentials? (C)

a. Contractile cells of the atria

b. Contractile cells of the ventricle

c. Purkinje cells of the ventricle

d. Smooth muscle cells of the coronary arteries

21. Within the conduction system of the heart, the preferred pathway by which impulses travel between the SA and AV nodes is called the: (A)

a. internodal path.

b. Bundle of His.

c. annulus fibrosus.

d. pectinate muscle.

22. The point at which about half of the atrium is depolarized is indicated by which point in the electrocardiogram (ECG or EKG)? (B)

a. Beginning of the P wave

b. Top of the P wave

c. Beginning of the QRS complex

d. Beginning of the T wave

23. Using the ECG (=EKG), the condition of atrial fibrillation would be indicated by the absence of: (A)

a. P waves.

b. QRS complexes.

c. T waves.

d. all of the above.

24. The condition in which the heart beats slower than normal is called: (B)

a. tachycardia.

b. bradycardia.

c. ventricular fibrillation.

d. an ectopic focus.

25. During the plateau phase of the action potential in contractile cells of the heart, the influx of Ca²⁺ ions into the cell: (B)

a. stimulates the opening of Na⁺ channels.

b. stimulates the release of Ca²⁺ from the sarcoplasmic reticulum (SR).

c. inhibits the release of Ca²⁺ from the SR.

d. inhibits cross bridge formation.

26. An agent which inhibits the Na⁺/K⁺ pump of contractile cells of the heart is considered to be a: (C)

a. positive chronotropic agent.

b. negative chronotropic agent.

c. positive inotropic agent.

d. negative inotropic agent.

27. During the cardiac cycle, the ventricular filling begins with: (B)

a. contraction of the atria.

b. opening of the mitral valve.

c. opening of the aortic semilunar valve.

d. closing of the aortic semilunar valve.

28. During the cardiac cycle, the period just before the opening of the aortic semilunar valve is called: (D)

a. rapid ventricular filling.

b. diastasis.

c. isovolumetric relaxation.

d. isovolumetric contraction.

29. Cardiac output is computed from the product of heart rate and: (C)

a. residual volume.

b. end diastolic volume.

c. stroke volume.

d. total peripheral resistance.

30. The term which describes the amount that the ventricles are stretched just before contraction is: (A)

a. preload.

b. afterload.

c. residual volume.

d. stroke volume.

31. Stroke volume is determined from which of the following relationships? (B)

a. Residual volume minus end diastolic volume

b. End diastolic volume minus residual volume

c. Preload minus afterload

d. Afterload minus preload

32. All of the following will increase stroke volume except: (C)

a. an increase in venous return due to exercise.

b. an increase in contractility due to sympathetic stimulation.

c. an increase in heart rate.