$$CO = 70 \times 75 = 5250 mL/$$min

Question 1

Which heart valve prevents backflow of blood from the left ventricle into the left atrium during ventricular systole?

Accepted Answer

Mitral (bicuspid) valve

Question 2

A blockage in which artery is most likely to cause a myocardial infarction affecting the anterior wall of the left ventricle?

Accepted Answer

Left anterior descending (LAD) artery

Question 3

Which layer of the heart contains the contractile muscle cells responsible for pumping blood?

Accepted Answer

Myocardium

Question 4

During the cardiac cycle, which event is represented by the QRS complex on an ECG?

Accepted Answer

Ventricular depolarization

Question 5

Which of the following best describes the function of intercalated discs in cardiac muscle?

Accepted Answer

They allow rapid transmission of electrical signals between cells.

Question 6

If a patient has a resting heart rate of 120 beats per minute, which term best describes this condition?

Accepted Answer

Tachycardia

Question 7

Which structure initiates the electrical impulse that triggers each heartbeat?

Accepted Answer

Sinoatrial (SA) node

Question 8

Calculate the cardiac output if the stroke volume is 70 mL and the heart rate is 75 beats per minute. Use the formula $$CO = SV 	imes HR.$$

Accepted Answer

$$CO = 70 	imes 75 = 5250 mL/$$min

Question 9

Which of the following is NOT a function of the coronary circulation?

Accepted Answer

Transporting blood from the heart to the lungs

Question 10

A patient with congestive heart failure is most likely to experience which of the following symptoms due to inadequate cardiac output?

Accepted Answer

Shortness of breath and fatigue

Question 11

Which of the following best explains why the left ventricle has a thicker myocardium than the right ventricle?

Accepted Answer

It pumps blood to the entire body, requiring higher pressure.

Question 12

Which heart sound (S1 or S2) is produced by the closure of the atrioventricular (AV) valves?

Accepted Answer

S1

Question 13

Which of the following is a direct effect of increased sympathetic stimulation on the heart?

Accepted Answer

Increased heart rate and contractility

Question 14

Which of the following best describes the role of chemoreceptors in regulating heart activity?

Accepted Answer

They sense changes in blood levels of CO$$_2$$, O$$_2$$, and pH.

Question 15

During which phase of the cardiac cycle do the ventricles fill with blood?

Accepted Answer

Diastole

Question 16

Which of the following is the correct sequence for the electrical conduction pathway in the heart?

Accepted Answer

SA node → AV node → Bundle of His → Purkinje fibers

Question 17

A patient’s ECG shows a prolonged PR interval. Which part of the conduction system is most likely affected?

Accepted Answer

AV node

Question 18

Which of the following is a common cause of congestive heart failure?

Accepted Answer

Coronary atherosclerosis

Question 19

If the stroke volume decreases but the heart rate remains constant, what happens to cardiac output? Use the formula $$CO = SV 	imes HR.$$

Accepted Answer

Cardiac output decreases

Question 20

Which of the following statements about systole is correct?

Accepted Answer

It is the phase when the ventricles contract and pump blood out of the heart.

Study Guide: The Cardiovascular System – The Heart (Chapter 18)

Study Guide - Practice Questions