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 at risk for ischemia?

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 → lungs → 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 and right ventricles is correct?

Accepted Answer

The left ventricle generates higher pressure to overcome greater resistance in the systemic circuit.

Question 10

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

Accepted Answer

First sound (lub); beginning of ventricular systole

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 distance blood travels in the pulmonary circuit is shorter.

Question 12

What is the primary function of the coronary circulation?

Accepted Answer

To deliver oxygen-rich blood to the myocardium

Question 13

Which of the following is a direct result of ventricular depolarization as seen on an ECG?

Accepted Answer

QRS complex

Question 14

A patient experiences a myocardial infarction (MI) that damages the SA node. What is the most likely effect on the heart’s rhythm?

Accepted Answer

The AV node will take over as pacemaker, resulting in a slower heart rate.

Question 15

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

Accepted Answer

They anchor the AV valve cusps to papillary muscles, preventing valve prolapse.

Question 16

Which of the following is a consequence of ventricular fibrillation if not corrected promptly?

Accepted Answer

Loss of coordinated electrical activity and possible death

Question 17

Which of the following best explains why atrial repolarization is not visible on a standard ECG?

Accepted Answer

It occurs at the same time as the QRS complex and is masked by it.

Question 18

Which of the following best describes the effect of a long absolute refractory period in cardiac muscle cells?

Accepted Answer

It prevents tetanus and ensures rhythmic contractions.

Question 19

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

Accepted Answer

Blood flows through multiple organ systems simultaneously, allowing independent regulation.

Question 20

Which of the following is the correct sequence of events during the cardiac cycle as shown in an ECG?

Accepted Answer

Atrial depolarization (P wave) → ventricular depolarization (QRS complex) → ventricular repolarization (T wave)

Cardiac Function and Electrical Activity: Anatomy & Physiology Study Guide

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드