$CO = 75 \times 80 = 6000$ mL/min

Question 1

During ventricular relaxation, which heart valves are open and which are closed?

Accepted Answer

Tricuspid and mitral (AV) valves are open; aortic and pulmonary semilunar valves are closed.

Question 2

Which structure electrically isolates the atrial myocardium from the ventricular myocardium?

Accepted Answer

Cardiac skeleton

Question 3

A patient has a damaged aortic valve that does not close fully. What is the most likely consequence?

Accepted Answer

Blood will regurgitate from the aorta into the left ventricle during diastole.

Question 4

Which of the following best describes atherosclerosis?

Accepted Answer

Thickening and stiffening of arterial walls due to lipid deposits within the wall.

Question 5

A patient with coronary artery disease undergoes a bypass surgery. Which vessel is most commonly used for the graft?

Accepted Answer

Great saphenous vein

Question 6

Which of the following is a major risk factor for atherosclerosis?

Accepted Answer

Smoking

Question 7

During the cardiac cycle, what event immediately follows ventricular systole?

Accepted Answer

Ventricular diastole

Question 8

Which formula correctly calculates cardiac output?

Accepted Answer

$CO = HR 	imes SV$

Question 9

If a patient has a heart rate of 75 bpm and a stroke volume of 80 mL/beat, what is their cardiac output?

Accepted Answer

$CO = 75 	imes 80 = 6000$ mL/min

Question 10

Which cells initiate the electrical signal that triggers heart contraction?

Accepted Answer

Pacemaker cells in the sinoatrial (SA) node

Question 11

What is the primary function of the Purkinje fibers in the heart's conduction system?

Accepted Answer

To rapidly propagate action potentials to ventricular myocardium

Question 12

Which phase of the cardiac muscle action potential prevents tetanus in the heart?

Accepted Answer

Plateau phase

Question 13

A patient has a blockage in the right bundle branch. Which part of the heart's conduction system is directly affected?

Accepted Answer

Propagation of action potentials to the right ventricle

Question 14

Which of the following best explains why cardiac muscle cannot enter tetanus?

Accepted Answer

The long absolute refractory period prevents summation of contractions.

Question 15

Which valve prevents backflow of blood from the right ventricle to the right atrium during ventricular contraction?

Accepted Answer

Tricuspid valve

Question 16

Which of the following procedures involves inserting a balloon to widen a narrowed artery?

Accepted Answer

Angioplasty

Question 17

What is the main difference between the cusps of semilunar valves and AV valves?

Accepted Answer

Semilunar valves have cup-like cusps that do not require chordae tendineae.

Question 18

Which event marks the beginning of ventricular systole?

Accepted Answer

Depolarization of ventricular myocardium by Purkinje fibers

Question 19

If the SA node is damaged, which structure can act as a backup pacemaker for the heart?

Accepted Answer

Atrioventricular (AV) node

Question 20

Which of the following best describes the effect of a stent placement in a coronary artery?

Accepted Answer

A tube is left in the artery to keep it open and prevent future blockages.

Chapter 18: The Heart – Structure, Function, and Physiology

Study Guide - Practice Questions