$$CO = Heart\ Rate \times Stroke\ Volume$$

Question 1

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

Accepted Answer

The heart lies in the mediastinum, with the apex directed toward the left hip.

Question 2

Which layer of the heart wall is responsible for the contractile function of the heart?

Accepted Answer

Myocardium

Question 3

What is the primary function of the chordae tendineae during ventricular contraction?

Accepted Answer

To prevent the eversion of the atrioventricular valve flaps

Question 4

Which of the following statements about the pulmonary and systemic circuits is correct?

Accepted Answer

The pulmonary circuit is shorter and operates under lower pressure than the systemic circuit.

Question 5

Which event is represented by the QRS complex on an ECG tracing?

Accepted Answer

Ventricular depolarization

Question 6

During which phase of the cardiac cycle is the end diastolic volume (EDV) found in the ventricles?

Accepted Answer

Ventricular filling

Question 7

Which formula correctly represents cardiac output (CO)?

Accepted Answer

$$CO = Heart\ Rate 	imes Stroke\ Volume$$

Question 8

A patient with hypertension (high blood pressure) is likely to experience which of the following changes in cardiac function?

Accepted Answer

Increased afterload and decreased stroke volume

Question 9

Which of the following best explains why the heart cannot undergo tetanus (sustained contraction)?

Accepted Answer

The absolute refractory period in cardiac muscle is as long as the contraction itself.

Question 10

Which of the following is a positive inotropic agent that increases contractility of the heart?

Accepted Answer

Epinephrine

Question 11

What is the main effect of parasympathetic stimulation on the heart?

Accepted Answer

It decreases heart rate by releasing acetylcholine at the SA and AV nodes.

Question 12

Which structure is responsible for setting the pace of the heart under normal conditions?

Accepted Answer

Sinoatrial (SA) node

Question 13

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

Accepted Answer

They allow ions to pass from cell to cell, enabling coordinated contraction.

Question 14

A patient is experiencing a blockage in the left pulmonary artery. Which of the following would most likely be affected?

Accepted Answer

Blood flow from the right ventricle to the lungs

Question 15

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

Accepted Answer

The greater the stretch of cardiac muscle cells before contraction, the stronger the contraction.

Question 16

Which of the following is true regarding the heart valves?

Accepted Answer

The mitral valve prevents backflow into the left atrium.

Question 17

During which phase of the cardiac cycle do the semilunar valves close, producing the 'dup' heart sound?

Accepted Answer

Isovolumetric relaxation

Question 18

If a patient’s heart rate is 90 beats/min and their stroke volume is 60 mL/beat, what is their cardiac output?

Accepted Answer

$$CO = 90 	imes 60 = 5400\ mL/min$$

Question 19

Which of the following best describes the sequence of electrical conduction through the heart?

Accepted Answer

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

Question 20

Which of the following would most likely result from a failure of the papillary muscles during ventricular contraction?

Accepted Answer

Backflow of blood from the ventricles into the atria

The Cardiovascular System: The Heart – Anatomy & Physiology Study Guide

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