Cardiac Output = Stroke Volume $$\times$$ Heart Rate $$CO = SV \times HR$$

Question 1

Which of the following best describes the path of blood flow through the heart and lungs in the pulmonary circuit?

Accepted Answer

Right ventricle → Pulmonary arteries → Lungs → Pulmonary veins → Left atrium

Question 2

A patient presents with chest pain and is diagnosed with a myocardial infarction. Which part of the heart's circulation is directly affected?

Accepted Answer

Coronary circulation

Question 3

Which valve prevents backflow of blood from the left ventricle to the left atrium during ventricular systole?

Accepted Answer

Mitral (bicuspid) valve

Question 4

What is the primary function of gap junctions in cardiac muscle cells?

Accepted Answer

Allow rapid electrical communication between cells

Question 5

During the sequence of excitation in the heart, which structure receives the electrical impulse immediately after the atrioventricular (AV) node?

Accepted Answer

Atrioventricular bundle (Bundle of His)

Question 6

Which of the following best describes the effect of the cardioaccelatory center on heart function?

Accepted Answer

Increases heart rate via sympathetic stimulation

Question 7

During the action potential of contractile cardiac cells, which ion is primarily responsible for the plateau phase?

Accepted Answer

Ca$$^{2+}$$

Question 8

A patient with hyperkalemia is at risk for which of the following cardiac complications?

Accepted Answer

Arrhythmias and feeble heartbeat

Question 9

Which equation correctly represents cardiac output?

Accepted Answer

Cardiac Output = Stroke Volume $$	imes$$ Heart Rate

$$CO = SV 	imes HR$$

Question 10

Which event is represented by the QRS complex on an electrocardiogram (ECG)?

Accepted Answer

Ventricular depolarization and atrial repolarization

Question 11

During ventricular filling (mid-to-late diastole), which volume is measured just before ventricular contraction?

Accepted Answer

End diastolic volume (EDV)

Question 12

Which heart sound is associated with the closing of the AV valves?

Accepted Answer

First heart sound (lub)

Question 13

A stenotic valve is most likely to cause which of the following?

Accepted Answer

A heart murmur due to restricted blood flow

Question 14

Which mechanism is responsible for removing Ca$$^{2+}$$ from the cytosol during cardiac muscle relaxation?

Accepted Answer

Ca$$^{2+}$$ ATPase in sarcoplasmic reticulum and plasma membrane, and Na$$^{+}-Ca$^{2+}$$ exchanger

Question 15

If a patient has left-sided congestive heart failure (CHF), which of the following is most likely to occur?

Accepted Answer

Pulmonary congestion due to backup of blood in the lungs

Question 16

Which of the following best describes the effect of preload on stroke volume?

Accepted Answer

Increased preload increases stroke volume by stretching cardiac muscle fibers

Question 17

Which phase of the cardiac cycle is characterized by all heart valves being closed and no change in ventricular volume?

Accepted Answer

Isovolumetric contraction

Question 18

Which of the following ions, if present in excess, can cause a feeble heartbeat and arrhythmias?

Accepted Answer

K$$^{+} ($$potassium)

Question 19

Which of the following best explains the role of calcium-induced calcium release in cardiac muscle contraction?

Accepted Answer

Ca$$^{2+}$$ entering the cell triggers release of more Ca$$^{2+}$$ from the sarcoplasmic reticulum

Question 20

A patient with tachycardia has a heart rate of 120 beats per minute and a stroke volume of 70 mL. What is their cardiac output?

$$CO = SV 	imes HR$$

Accepted Answer

$$CO = 70 	imes 120 = 8400 mL/$$min

Ch. 19 The Cardiovascular System: The Heart – Study Guide

Study Guide - Practice Questions