Question 1

Which structure in the heart is primarily responsible for initiating the electrical impulse that triggers each heartbeat, and what is its typical firing rate at rest?

Accepted Answer

Sinoatrial (SA) node; 70–80 AP/min

Question 2

During which phase of the cardiac action potential does the permeability to $$\mathrm{Ca$$^{2+}$$}$$ increase and permeability to $$\mathrm{K^+}$$ decrease, resulting in the plateau phase?

Accepted Answer

Phase 2

Question 3

A patient presents with a blockage in the circumflex coronary artery. Which region of the heart is most likely to be affected by this blockage?

Accepted Answer

Left ventricle

Question 4

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

Accepted Answer

Mitral (bicuspid) valve

Question 5

What is the significance of the delay at the atrioventricular (AV) node during the cardiac cycle?

Accepted Answer

It allows the atria to finish contracting and complete ventricular filling.

Question 6

Which of the following best describes the flow of blood through the heart and major vessels in the systemic and pulmonary circuits?

Accepted Answer

Left ventricle → aorta → systemic circuit → vena cavae → right atrium → right ventricle → pulmonary artery → pulmonary circuit → pulmonary veins → left atrium → left ventricle

Question 7

Which component of the cardiac muscle cell structure allows for rapid electrical communication between cells, enabling coordinated contraction?

Accepted Answer

Gap junctions

Question 8

A patient’s ECG shows a loss of the 1-to-1 relationship between P waves and QRS complexes. What is the most likely diagnosis?

Accepted Answer

Second-degree heart block

Question 9

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

Accepted Answer

It pumps blood into the systemic circuit and has a thicker wall than the right ventricle.

Question 10

Which heart sound is associated with the closing of the semilunar valves, and what phase of the cardiac cycle does it signify?

Accepted Answer

Second sound (dup); beginning of ventricular diastole

Question 11

Which of the following best explains why the pulmonary circuit is a low-pressure system compared to the systemic circuit?

Accepted Answer

The pulmonary capillaries are delicate and the distance traveled is small.

Question 12

Which of the following is a function of the coronary circulation?

Accepted Answer

Delivering oxygen-rich blood to the myocardium

Question 13

A patient has a heart murmur due to a faulty mitral valve. Which of the following is a likely consequence?

Accepted Answer

Backflow of blood into the left atrium during ventricular contraction

Question 14

Which of the following best describes the QRS complex on an ECG?

Accepted Answer

Ventricular depolarization

Question 15

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 contractions.

Question 16

Which of the following best explains why the heart is considered a double pump?

Accepted Answer

It pumps blood through both the pulmonary and systemic circuits.

Question 17

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

Accepted Answer

The T wave on the ECG

Question 18

Which of the following best describes the function of the chordae tendineae?

Accepted Answer

They prevent the atrioventricular valve cusps from everting into the atria during ventricular contraction.

Question 19

Which of the following best explains the importance of parallel blood flow in the systemic circuit?

Accepted Answer

It allows independent regulation of blood flow to different organs.

Question 20

A patient’s ECG shows a P wave that is not followed by a QRS complex. What is the most likely explanation?

Accepted Answer

There is a block in the conduction through the AV node.

Cardiac Function and Electrical Activity: Anatomy & Physiology Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드