Q: If a patient has a stroke volume ($$SV) of$$ $$70\,mL$$ and a heart rate ($$HR) of$$ $$75\,beats/min$$, what is their cardiac output ($$CO) in $$liters per minute?

$$CO = 70 \times 75 = 5250\,mL/min = 5.25\,L/min$$

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 sternum and vertebral column, and between the lungs.

Question 2

A patient is found to have a thickened left ventricular wall. Which of the following best explains why the left ventricle has a thicker myocardium than the right ventricle?

Accepted Answer

The left ventricle pumps blood to the entire systemic circulation, requiring higher pressure to overcome greater resistance.

Question 3

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

Accepted Answer

Tricuspid valve

Question 4

During which phase of the cardiac cycle do the atrioventricular (AV) valves close and the semilunar valves open?

Accepted Answer

Ventricular systole

Question 5

Which of the following best describes the function of the fibrous skeleton of the heart?

Accepted Answer

It provides electrical insulation between the atria and ventricles, supports the heart valves, and serves as an attachment point for cardiac muscle.

Question 6

A patient has a blockage in the left anterior descending (LAD) artery. Which area of the heart is most likely to be affected by this blockage?

Accepted Answer

Both ventricles, especially the anterior walls

Question 7

Which of the following statements about the conduction system of the heart is correct?

Accepted Answer

The sinoatrial (SA) node acts as the primary pacemaker, firing at 90-100 times per minute.

Question 8

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

Accepted Answer

To ensure the heart can fill with blood before the next contraction and prevent tetanus.

Question 9

A patient presents with a heart rate of 40 beats per minute. Which part of the conduction system is most likely acting as the pacemaker in this scenario?

Accepted Answer

Atrioventricular (AV) node

Question 10

Which of the following best describes the sequence of events during a normal cardiac action potential in a ventricular muscle cell?

Accepted Answer

Rapid Na+ influx (depolarization), plateau phase with Ca2+ entry, repolarization with K+ exit

Question 11

A patient with congestive heart failure has fluid accumulation in the lungs. Which side of the heart is most likely failing, and what is the physiological consequence?

Accepted Answer

Left side; pulmonary edema

Question 12

Which of the following equations correctly represents cardiac output ($$CO$$)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 13

If a patient has a stroke volume ($$SV) of$$ $$70\,mL$$ and a heart rate ($$HR) of$$ $$75\,beats/min$$, what is their cardiac output ($$CO) in $$liters per minute?

Accepted Answer

$$CO = 70 	imes 75 = 5250\,mL/min = 5.25\,L/min$$

Question 14

Which of the following best describes the Frank-Starling Law of the Heart?

Accepted Answer

The greater the stretch of cardiac muscle fibers during filling, the stronger the force of contraction.

Question 15

Which of the following is a major risk factor for coronary artery disease due to its role in promoting the formation of fatty plaques?

Accepted Answer

High levels of low-density lipoproteins (LDLs)

Question 16

A patient is diagnosed with a myocardial infarction. Which of the following best describes what has occurred?

Accepted Answer

Death of an area of heart muscle due to lack of oxygen, replaced with scar tissue.

Question 17

Which of the following best explains why both the right and left ventricles must eject the same volume of blood during each cardiac cycle?

Accepted Answer

To prevent accumulation of blood in either the pulmonary or systemic circulation.

Question 18

Which of the following heart sounds is associated with the closing of the semilunar valves?

Accepted Answer

Second heart sound (dupp)

Question 19

Which of the following best describes the effect of aerobic exercise on the cardiovascular system?

Accepted Answer

Increases cardiac output, increases HDL, decreases triglycerides, and improves lung function.

Question 20

A patient with a genetic predisposition to heart disease is found to have high blood pressure and high blood cholesterol. Which of the following best explains how these factors contribute to coronary artery disease?

Accepted Answer

They promote the formation of atherosclerotic plaques, narrowing coronary arteries and reducing oxygen supply to the heart.

Cardiovascular System: The Heart – Structure, Location, and Orientation

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