Question 1

Which of the following correctly describes the structure and location of the tricuspid and bicuspid (mitral) valves in the heart?

Accepted Answer

The tricuspid valve is located between the right atrium and right ventricle; the bicuspid (mitral) valve is between the left atrium and left ventricle.

Question 2

Which of the following best describes the function of the aortic and pulmonary semilunar valves?

Accepted Answer

They prevent backflow of blood into the ventricles after ventricular contraction.

Question 3

Which of the following correctly traces the path of blood through the heart and pulmonary circulation?

Accepted Answer

Right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta

Question 4

Why does the myocardium require its own blood supply, and from where do the right and left coronary arteries branch?

Accepted Answer

Because the myocardium is too thick for diffusion; the coronary arteries branch from the base of the aorta.

Question 5

What is an anastomosis, and why are anastomoses important in coronary circulation?

Accepted Answer

A direct connection between two arteries or vessels; they provide alternate routes for blood flow if one vessel is blocked.

Question 6

Into which vessel do all the coronary veins drain, and into which part of the heart does this vessel empty?

Accepted Answer

Coronary sinus; right atrium

Question 7

How do conducting cells in the myocardium differ from contractile cells?

Accepted Answer

Conducting cells spontaneously depolarize and transmit electrical signals; contractile cells respond to these signals by contracting.

Question 8

Which structure in the heart's intrinsic conduction system acts as the normal pacemaker?

Accepted Answer

SA node

Question 9

What could cause the development of an ectopic pacemaker in the heart?

Accepted Answer

Damage to the SA node, allowing other conducting cells to initiate impulses

Question 10

What causes the conducting cells in the myocardium to depolarize, and what role do calcium ions play in this process?

Accepted Answer

Depolarization is caused by sodium influx; calcium ions prolong the action potential and contraction.

Question 11

Why is the long refractory period in cardiac muscle cells necessary for proper heart function?

Accepted Answer

It prevents tetanic contractions, ensuring the heart can relax and refill with blood between beats.

Question 12

Which of the following best describes how an electrocardiogram (ECG) is obtained and what it detects?

Accepted Answer

By recording electrical activity of the heart via skin electrodes; it detects depolarization and repolarization of cardiac muscle.

Question 13

During which part of the ECG does atrial depolarization occur, and what is the contractile status of the atria at this time?

Accepted Answer

P wave; atria are in systole (contracting)

Question 14

What does the QRS complex of the ECG represent?

Accepted Answer

Ventricular depolarization

Question 15

What is the PR (PQ) interval on an ECG, and what is its clinical significance?

Accepted Answer

The time from the start of atrial depolarization to the start of ventricular depolarization; it indicates AV node conduction time.

Question 16

A patient’s ECG shows an abnormally elevated ST segment. What could this indicate?

Accepted Answer

Myocardial infarction (heart attack)

Question 17

Which of the following equations best represents the relationship between cardiac output ($CO$), heart rate ($HR$), and stroke volume ($SV$)?

Accepted Answer

$CO = HR 	imes SV$

Question 18

If a patient has a heart rate of $80$ beats per minute and a stroke volume of $70$ mL per beat, what is their cardiac output?

Accepted Answer

$5600$ mL/min

Question 19

Which of the following best explains why calcium channel blockers are used to treat certain cardiac arrhythmias?

Accepted Answer

They decrease calcium influx, reducing the strength and rate of cardiac muscle contraction.

Question 20

A patient’s ECG shows a prolonged PR interval. Which of the following is the most likely explanation?

Accepted Answer

Delayed conduction through the AV node

Cardiac Anatomy, Physiology, and Electrophysiology Study Guide

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