$$CO = 75 \times 80 = 6000 mL/$$min

Question 1

Which of the following best describes the function of the pericardial fluid found between the parietal and visceral layers of the pericardium?

Accepted Answer

It reduces friction between the heart and surrounding structures during contraction.

Question 2

A patient suffers damage to the semilunar valve of the right ventricle. Which vessel will be directly affected in terms of blood flow?

Accepted Answer

Pulmonary trunk

Question 3

During which phase of the cardiac cycle are the AV valves closed and the semilunar valves open?

Accepted Answer

Ventricular systole

Question 4

Which of the following statements about the left ventricle is correct?

Accepted Answer

It produces higher pressure to propel blood through the systemic circuit.

Question 5

What is the primary reason that cardiac muscle cannot undergo tetanus like skeletal muscle?

Accepted Answer

The long refractory period in cardiac muscle prevents summation of contractions.

Question 6

If the SA node fails to function, what is the expected heart rate set by the AV node?

Accepted Answer

40–60 beats per minute

Question 7

Which of the following best explains the Frank-Starling principle?

Accepted Answer

The more the heart muscle is stretched by increased venous return, the harder it contracts, increasing stroke volume.

Question 8

A patient is experiencing bradycardia. Which of the following best describes this condition?

Accepted Answer

A heart rate slower than 60 beats per minute

Question 9

Which of the following events is represented by the QRS complex in an electrocardiogram (ECG)?

Accepted Answer

Ventricular depolarization and hidden atrial repolarization

Question 10

Calculate the cardiac output if the heart rate is 75 beats per minute and the stroke volume is 80 mL per beat. Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 75 	imes 80 = 6000 mL/$$min

Question 11

Which of the following would most likely result from stimulation of acetylcholine (ACh) receptors in the heart?

Accepted Answer

Decreased heart rate and decreased cardiac output

Question 12

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

Accepted Answer

Left ventricle and interventricular septum

Question 13

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

Accepted Answer

They prevent the AV valve cusps from inverting into the atria during ventricular contraction.

Question 14

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

Accepted Answer

Increased heart rate and increased contractility

Question 15

A patient with a damaged cardioinhibitory center in the medulla oblongata would most likely experience which of the following?

Accepted Answer

Decreased parasympathetic activity and increased heart rate

Question 16

Which of the following best explains why the left ventricular wall is much thicker than the right ventricular wall?

Accepted Answer

It must generate higher pressure to pump blood through the systemic circuit.

Question 17

If venous return to the heart increases, what is the expected effect on stroke volume according to the Frank-Starling principle?

Accepted Answer

Stroke volume increases.

Question 18

Which of the following is the correct sequence of structures that an action potential travels through in the heart's conducting system?

Accepted Answer

SA node → AV node → AV bundle → bundle branches → Purkinje fibers

Question 19

A patient is found to have a prolonged P-R interval on their ECG. What does this most likely indicate?

Accepted Answer

Possible damage to the conducting pathways or AV node

Question 20

Which of the following best describes the effect of thyroid hormones on the heart?

Accepted Answer

They increase heart rate and force of contraction.

The Cardiovascular System: The Heart – Study Notes

Study Guide - Practice Questions