Question 1

Which of the following best describes the location of the heart within the thoracic cavity?

Accepted Answer

It is situated in the mediastinum, slightly to the left, within the pericardial cavity.

Question 2

Which structure prevents the backflow of blood from the left ventricle into the left atrium during ventricular contraction?

Accepted Answer

Mitral (bicuspid) valve

Question 3

A patient presents with a heart murmur due to a stenotic valve. Which of the following best describes a stenotic valve?

Accepted Answer

A valve with calcium deposits making it hard and inflexible, impeding blood ejection.

Question 4

Which of the following is a function of the fibrous skeleton of the heart?

Accepted Answer

It acts as an insulator for the heart’s electrical activity.

Question 5

During the cardiac cycle, which event directly causes the S1 ('lub') heart sound?

Accepted Answer

Closure of the atrioventricular valves

Question 6

Which of the following equations correctly calculates cardiac output ($CO$)?

Accepted Answer

$CO = HR 	imes SV$

Question 7

A patient with left ventricular failure is most likely to develop which of the following complications?

Accepted Answer

Pulmonary edema due to pulmonary congestion

Question 8

Which of the following best explains the Frank-Starling law of the heart?

Accepted Answer

The more the ventricular muscle cells are stretched, the more forcefully they contract.

Question 9

Which of the following is a positive chronotropic agent?

Accepted Answer

Sympathetic nervous system stimulation

Question 10

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

Accepted Answer

They allow ions to pass from one cell to the next, enabling the heart to contract as a unit.

Question 11

A patient is diagnosed with myocardial infarction (MI). Which of the following best explains the underlying cause?

Accepted Answer

A rupture of plaques and formation of a clot that obstructs blood flow, resulting in death of cardiac muscle cells.

Question 12

Which of the following is true regarding the pulmonary and systemic circuits?

Accepted Answer

The right side of the heart pumps blood to the pulmonary circuit, which is a low-pressure circuit.

Question 13

Which of the following best describes the plateau phase in a contractile cardiac muscle cell action potential?

Accepted Answer

It is due to the slow opening of calcium ion channels and the simultaneous outflow of potassium ions.

Question 14

Which of the following is the correct formula for calculating stroke volume ($SV$)?

Accepted Answer

$SV = EDV - ESV$

Question 15

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

Accepted Answer

Decreased stroke volume

Question 16

Which of the following best describes the role of the atrioventricular (AV) node delay?

Accepted Answer

It allows time for the ventricles to fill with blood before they contract.

Question 17

Which of the following is a characteristic of ventricular fibrillation?

Accepted Answer

It is immediately life-threatening and requires defibrillation.

Question 18

Which of the following best explains why cardiac muscle cannot enter tetany (sustained contraction)?

Accepted Answer

The presence of the plateau phase in the action potential lengthens the refractory period.

Question 19

Which of the following is a function of atrial natriuretic peptide (ANP) released by the heart?

Accepted Answer

It decreases sodium retention in the kidneys, lowering blood pressure.

Question 20

A patient with a heart block at the AV node would most likely show which of the following changes on an ECG?

Accepted Answer

A longer P-R interval and/or extra P waves

The Cardiovascular System: The Heart – Structured Study Notes

Study Guide - Practice Questions