Question 1

Which layer of the heart wall is responsible for generating action potentials and contraction?

Accepted Answer

Myocardium

Question 2

What is the primary function of the chordae tendineae and papillary muscles during ventricular systole?

Accepted Answer

To prevent prolapse of the AV valve flaps into the atria

Question 3

Which of the following best describes the role of gap junctions in cardiac muscle cells?

Accepted Answer

They allow direct communication of contraction signals between cells

Question 4

During which phase of the cardiac cycle do the atrioventricular (AV) valves open?

Accepted Answer

Ventricular diastole

Question 5

Which chamber of the heart receives oxygenated blood from the lungs?

Accepted Answer

Left atrium

Question 6

What is the correct formula for calculating stroke volume (SV)?

Accepted Answer

$$SV = EDV - ESV$$

Question 7

A patient has an end diastolic volume (EDV) of 120 mL and an end systolic volume (ESV) of 50 mL. What is their stroke volume (SV)?

Accepted Answer

70 mL

Question 8

Which of the following statements about the pericardial cavity is correct?

Accepted Answer

It contains serous fluid to decrease friction during heartbeats

Question 9

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

Accepted Answer

Tricuspid valve

Question 10

What is the main function of the coronary arteries?

Accepted Answer

To supply oxygenated blood to the heart wall

Question 11

Which of the following is a consequence of a stenotic heart valve?

Accepted Answer

Blood flow through the valve is restricted, causing a high-pitched sound

Question 12

Which structure is the heart's natural pacemaker?

Accepted Answer

Sinoatrial (SA) node

Question 13

If the AV node fails to conduct some SA node impulses, what ECG abnormality is most likely to be observed?

Accepted Answer

Second-degree heart block

Question 14

Which of the following best explains why tetanic contractions do not occur in cardiac muscle?

Accepted Answer

The absolute refractory period is long, preventing rapid re-excitation

Question 15

Which of the following would most likely increase cardiac output (CO)?

Accepted Answer

Increased venous return rate (VRR)

Question 16

A patient with a resting heart rate of 110 BPM is experiencing which condition?

Accepted Answer

Tachycardia

Question 17

Which of the following is the correct formula for cardiac output (CO)?

Accepted Answer

$$CO = SV 	imes HR$$

Question 18

Which of the following would most likely decrease heart rate (HR)?

Accepted Answer

Activation of the parasympathetic nervous system via the vagus nerve

Question 19

Which of the following is a direct effect of increased extracellular potassium (K+) on cardiac muscle contraction?

Accepted Answer

Decreased force of contraction

Question 20

Which of the following best describes the function of the pulmonary semilunar valve?

Accepted Answer

Prevents backflow of blood from the pulmonary trunk into the right ventricle

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

Study Guide - Practice Questions