Q: During the cardiac cycle, what is the stroke volume (SV) if the end-diastolic volume (EDV) is 120 mL and the end-systolic volume (ESV) is 50 mL?

SV = EDV - ESV = 120\,\text{mL} - 50\,\text{mL} = 70\,\text{mL}

Q: A patient has a heart rate of 90 beats per minute and a stroke volume of 65 mL per beat. What is their cardiac output?

CO = HR \times SV = 90 \times 65 = 5850\,\text{mL/min}

Question 1

Which of the following best describes the function of the pulmonary circuit?

Accepted Answer

It carries blood to and from the gas exchange surfaces of the lungs.

Question 2

During ventricular systole, which event occurs FIRST?

Accepted Answer

Ventricles contract and build pressure, closing AV valves and producing isovolumetric contraction.

Question 3

A patient presents with intense, persistent chest pain radiating to the arms and neck. Blood studies reveal elevated cardiac troponin T and CK-MB. What is the most likely diagnosis?

Accepted Answer

Myocardial infarction (MI)

Question 4

Which structure electrically insulates the ventricular cells from the atrial cells, stabilizes heart valves, and prevents overexpansion of the heart?

Accepted Answer

Cardiac skeleton

Question 5

If a patient has a blockage in the left coronary artery, which region of the heart is most likely to be affected?

Accepted Answer

Left ventricle, left atrium, and interventricular septum

Question 6

Which of the following equations correctly represents cardiac output?

Accepted Answer

CO = HR 	imes SV

Question 7

A patient with valvular heart disease (VHD) is most likely to experience which of the following complications?

Accepted Answer

Regurgitation of blood through the affected valve

Question 8

Which of the following best explains why cardiac contractile cells cannot undergo tetany?

Accepted Answer

The action potential duration is much longer than in skeletal muscle, preventing summation.

Question 9

During the cardiac cycle, what is the stroke volume (SV) if the end-diastolic volume (EDV) is 120 mL and the end-systolic volume (ESV) is 50 mL?

Accepted Answer

SV = EDV - ESV = 120\,	ext{mL} - 50\,	ext{mL} = 70\,	ext{mL}

Question 10

Which of the following drugs would be most appropriate to reduce coagulation in a patient at risk for myocardial infarction?

Accepted Answer

Aspirin

Question 11

Which of the following statements about the SA node is correct?

Accepted Answer

It establishes the sinus rhythm by depolarizing first.

Question 12

A patient has a heart rate of 90 beats per minute and a stroke volume of 65 mL per beat. What is their cardiac output?

Accepted Answer

CO = HR 	imes SV = 90 	imes 65 = 5850\,	ext{mL/min}

Question 13

Which of the following is a consequence of increased afterload on the left ventricle?

Accepted Answer

Stroke volume decreases

Question 14

Which of the following best describes the Frank–Starling Principle?

Accepted Answer

As end-diastolic volume (EDV) increases, stroke volume increases.

Question 15

Which of the following is TRUE regarding the role of calcium ions in cardiac muscle contraction?

Accepted Answer

Entry of extracellular $$Ca^{2+}$$ triggers release of additional $$Ca^{2+}$$ from the sarcoplasmic reticulum.

Question 16

Which of the following best explains the Bainbridge reflex?

Accepted Answer

It increases heart rate in response to increased venous return.

Question 17

A patient is diagnosed with pericarditis. Which of the following is a possible complication?

Accepted Answer

Cardiac tamponade due to excess fluid in the pericardial cavity

Question 18

Which of the following correctly matches the heart sound with its cause?

Accepted Answer

S1—Loud sound as AV valves close

Question 19

Which of the following is a plausible effect of sympathetic stimulation on the heart?

Accepted Answer

Increased heart rate and increased contractility

Question 20

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

Accepted Answer

They prevent the AV valves from opening backward during ventricular contraction.

Chapter 20: The Heart – Structure, Function, and Regulation

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