$$CO = HR \times SV = 75\ \mathrm{beats/min} \times 70\ \mathrm{mL/beat} = 5250\ \mathrm{mL/min}$$

Question 1

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

Accepted Answer

It is located in the mediastinum, between the lungs and above the diaphragm.

Question 2

Which chamber of the heart receives oxygen-poor blood from the systemic circulation?

Accepted Answer

Right atrium

Question 3

The thickest wall of the heart is found in which chamber, and why?

Accepted Answer

Left ventricle, because it must generate high pressure to pump blood through the systemic circuit.

Question 4

Which of the following correctly traces the path of blood flow through the heart and lungs?

Accepted Answer

Right atrium → right ventricle → pulmonary trunk → lungs → left atrium → left ventricle → aorta

Question 5

Which structure prevents backflow of blood from the left ventricle into the left atrium during ventricular contraction?

Accepted Answer

Mitral (bicuspid) valve

Question 6

A patient has a blockage in the anterior interventricular artery. Which area of the heart is most at risk for ischemia?

Accepted Answer

Anterior wall of the left ventricle

Question 7

Which of the following best explains why the left ventricle has a circular chamber and a thicker wall compared to the right ventricle?

Accepted Answer

It must generate higher pressure to pump blood throughout the systemic circulation.

Question 8

Which of the following equations correctly calculates stroke volume (SV)?

Accepted Answer

$$SV = EDV - ESV$$

Question 9

If a patient has an end-diastolic volume (EDV) of 120 mL and an end-systolic volume (ESV) of 50 mL, what is their stroke volume (SV)?

Accepted Answer

$$SV = 120\ \mathrm{mL} - 50\ \mathrm{mL} = 70\ \mathrm{mL}$$

Question 10

A patient’s heart rate (HR) is 75 beats per minute and their stroke volume (SV) is 70 mL/beat. What is their cardiac output (CO)?

Accepted Answer

$$CO = HR 	imes SV = 75\ \mathrm{beats/min} 	imes 70\ \mathrm{mL/beat} = 5250\ \mathrm{mL/min}$$

Question 11

Which of the following statements about the pericardium is correct?

Accepted Answer

The visceral and parietal pericardia are continuous and form a double-layered sac around the heart.

Question 12

Which of the following best describes the function of the cardiac conduction system?

Accepted Answer

It coordinates the timing of heart muscle contraction to ensure efficient pumping.

Question 13

A patient’s ECG shows an abnormal rhythm. Which part of the heart is most likely malfunctioning if the SA node fails?

Accepted Answer

The AV node may take over as the pacemaker, but at a slower rate.

Question 14

During which phase of the cardiac cycle do the semilunar valves open?

Accepted Answer

Ventricular systole (ventricular contraction)

Question 15

Which of the following best explains why the absolute refractory period in cardiac muscle is longer than in skeletal muscle?

Accepted Answer

It prevents tetanus and ensures the heart has time to fill with blood between contractions.

Question 16

Which of the following is a direct effect of sympathetic nervous system stimulation on the heart?

Accepted Answer

Increased heart rate and increased force of contraction

Question 17

A patient with a damaged left ventricle is likely to experience which of the following symptoms?

Accepted Answer

Reduced systemic blood flow and possible pulmonary congestion

Question 18

Which of the following best describes the function of the coronary arteries?

Accepted Answer

They supply oxygenated blood to the myocardium.

Question 19

If the cardiac output (CO) is 5 L/min and the heart rate (HR) is 70 beats/min, what is the stroke volume (SV)?

Accepted Answer

$$SV = \frac{CO}{HR} = \frac{5000\ \mathrm{mL/min}}{70\ \mathrm{beats/min}} \approx 71.4\ \mathrm{mL/beat}$$

Chapter 17: The Heart – Structure, Function, and Circulation

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