Question 1

Which of the following best describes the correct sequence of blood flow through the heart and major vessels, starting at the right atrium?

Accepted Answer

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

Question 2

Which of the following structures is responsible for initiating the action potential that triggers the heartbeat?

Accepted Answer

Sinoatrial (SA) node

Question 3

During the cardiac cycle, which event directly causes the second heart sound ('dub')?

Accepted Answer

Closure of the semilunar valves

Question 4

Which of the following best explains the process of excitation-contraction coupling (EC-coupling) in cardiac muscle?

Accepted Answer

Action potential triggers Ca2+ influx, which induces further Ca2+ release from the sarcoplasmic reticulum

Question 5

A patient has an end-diastolic volume (EDV) of 140 mL and an end-systolic volume (ESV) of 60 mL. What is the stroke volume (SV)? Use the formula $$SV = EDV - ESV.$$

Accepted Answer

$$SV = 140\ \mathrm{mL} - 60\ \mathrm{mL} = 80\ \mathrm{mL}$$

Question 6

Which of the following best describes the function of the Na+-Ca2+ exchanger (NCX) in cardiac muscle cells?

Accepted Answer

It pumps Na+ into the cell and Ca2+ out of the cell during relaxation

Question 7

Which phase of the cardiac action potential in contractile cells is primarily responsible for the plateau phase, and what ion movement causes it?

Accepted Answer

Phase 2; Ca2+ influx through L-type calcium channels

Question 8

A patient’s ECG shows a prolonged PR segment. Which part of the heart’s conduction system is most likely affected?

Accepted Answer

Atrioventricular (AV) node

Question 9

Which of the following best describes the relationship between heart rate (HR), stroke volume (SV), and cardiac output (CO)? Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = HR 	imes SV$$

Question 10

Which of the following changes would most likely increase cardiac output, assuming all other factors remain constant?

Accepted Answer

Increased heart rate and increased stroke volume

Question 11

During which phase of the cardiac cycle does isovolumetric ventricular contraction occur, and what is happening to the heart valves at this time?

Accepted Answer

Ventricular systole; both AV and semilunar valves are closed

Question 12

Which of the following best explains the role of HCN channels in pacemaker cells of the heart?

Accepted Answer

They allow Na+ influx during the pacemaker potential, contributing to spontaneous depolarization

Question 13

A patient’s ECG shows an abnormally tall and peaked T wave. Which electrolyte imbalance is most likely responsible?

Accepted Answer

Hyperkalemia (elevated K+)

Question 14

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

Accepted Answer

The greater the end-diastolic volume, the greater the force of contraction

Question 15

Which of the following best explains why the left ventricular wall is thicker than the right ventricular wall?

Accepted Answer

It pumps blood to the systemic circulation, which has higher resistance than the pulmonary circulation

Question 16

Which of the following is the correct order of electrical conduction through the heart?

Accepted Answer

SA node → AV node → Bundle of His → Purkinje fibers

Question 17

If a patient’s heart rate is 75 beats per minute and their stroke volume is 70 mL, what is their cardiac output? Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 75 	imes 70 = 5250\ \mathrm{mL/min}$$

Question 18

Which of the following best describes the function of the atrioventricular (AV) valves?

Accepted Answer

They prevent backflow of blood from the ventricles into the atria during ventricular contraction

Question 19

Which of the following best explains the significance of the refractory period in cardiac muscle?

Accepted Answer

It prevents tetanus by ensuring the heart muscle relaxes between contractions

Anatomy & Physiology Study Notes: The Heart and Cardiovascular System

Guida di studio - Domande di pratica

Study guide - Flashcard