Question 1

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

Accepted Answer

The heart is located in the mediastinum, between the lungs and superior to the diaphragm.

Question 2

Which layer of the heart wall is responsible for the contractile force that pumps blood?

Accepted Answer

Myocardium

Question 3

What is the primary function of the chordae tendineae in the heart?

Accepted Answer

To prevent the atrioventricular valves from inverting into the atria during ventricular contraction

Question 4

Which of the following statements about the left ventricle is correct?

Accepted Answer

It pumps blood into the aorta and has the thickest myocardium.

Question 5

A patient experiences chest pain due to partial obstruction of coronary blood flow. What is the most likely physiological cause of this pain?

Accepted Answer

Anaerobic fermentation in cardiac muscle producing lactic acid

Question 6

Which of the following best explains why the heart can continue to beat even if all nervous connections are cut?

Accepted Answer

The heart contains autorhythmic pacemaker cells that generate action potentials independently.

Question 7

During which phase of the cardiac muscle action potential does the plateau occur, and what is its significance?

Accepted Answer

During the plateau phase; it prolongs contraction to allow for efficient blood ejection and prevents tetanus.

Question 8

Which of the following is the correct sequence of structures that an electrical impulse travels through in the cardiac conduction system?

Accepted Answer

SA node → AV node → AV bundle (bundle of His) → Bundle branches → Purkinje fibers

Question 9

Which event is represented by the QRS complex on an electrocardiogram (ECG)?

Accepted Answer

Ventricular depolarization

Question 10

A patient’s ECG shows no P wave and a slower heart rate. Which of the following is the most likely explanation?

Accepted Answer

The AV node is acting as the pacemaker due to SA node failure.

Question 11

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

Accepted Answer

They allow ions to flow between cells, enabling coordinated contraction.

Question 12

Which of the following equations correctly represents the relationship between cardiac output, heart rate, and stroke volume?

Accepted Answer

$$CO = HR 	imes SV$$

Question 13

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

Accepted Answer

Mitral (bicuspid) valve

Question 14

What is the main reason the left ventricle has a thicker wall than the right ventricle?

Accepted Answer

It must generate higher pressure to overcome greater resistance in the systemic circuit.

Question 15

Which of the following best explains why myocardial infarction (MI) can lead to rapid muscle death?

Accepted Answer

The heart switches to anaerobic metabolism, which cannot sustain cardiac muscle for long.

Question 16

Which of the following is true regarding the refractory period in cardiac muscle cells?

Accepted Answer

It prevents tetanus and allows the heart to fill with blood between beats.

Question 17

Which of the following best describes the effect of sympathetic stimulation on the heart?

Accepted Answer

It increases heart rate and contraction strength.

Question 18

During which phase of the cardiac cycle do the semilunar valves open?

Accepted Answer

When ventricular pressure exceeds pressure in the aorta and pulmonary trunk

Question 19

Which of the following is a direct result of ventricular repolarization?

Accepted Answer

Closure of the semilunar valves (S2 heart sound)

Question 20

A patient has a bundle branch block. Which of the following is most likely to be observed on their ECG?

Accepted Answer

Widened QRS complex

The Heart: Structure, Function, and Physiology

Study Guide - Practice Questions