Q: A patient has a heart rate of 90 beats/min and a stroke volume of 60 mL/beat. What is their cardiac output?

$$CO = 90 \times 60 = 5400 mL/$$min

Question 1

Which of the following best describes the difference between the pulmonary and systemic circuits of the cardiovascular system?

Accepted Answer

The pulmonary circuit carries oxygen-poor blood from the right side of the heart to the lungs for gas exchange and back, while the systemic circuit supplies oxygenated blood from the left side of the heart to the body tissues.

Question 2

A patient presents with swelling in the ankles and distension of the jugular veins. Which cardiac condition is most likely responsible for these symptoms?

Accepted Answer

Right ventricular failure causing systemic edema

Question 3

Which layer of the heart wall is responsible for the contractile force that ejects blood from the heart, and what is its unique structural feature?

Accepted Answer

Myocardium; composed of spiraling cardiac muscle fibers that produce a wringing motion during contraction

Question 4

During ventricular systole, which valves are open and which are closed?

Accepted Answer

Semilunar valves are open; AV valves are closed

Question 5

Which equation correctly calculates cardiac output ($$CO) $$given heart rate ($$HR) $$and stroke volume ($$SV$$)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 6

A patient has a heart rate of 90 beats/min and a stroke volume of 60 mL/beat. What is their cardiac output?

Accepted Answer

$$CO = 90 	imes 60 = 5400 mL/$$min

Question 7

Which of the following best explains why the SA node acts as the heart's pacemaker?

Accepted Answer

It has the fastest rate of spontaneous depolarization due to a slow Na$$^+$$ inflow that creates a pacemaker potential.

Question 8

Which of the following is a consequence of hyperkalemia on cardiac function?

Accepted Answer

Decreased heart rate and irregular rhythm due to reduced excitability of the myocardium

Question 9

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

Accepted Answer

Isovolumetric contraction

Question 10

A patient with a blockage in the left anterior descending (LAD) artery is at risk for which of the following?

Accepted Answer

Ischemia of both ventricles and anterior two-thirds of the interventricular septum

Question 11

Which of the following best describes the Frank-Starling law of the heart?

Accepted Answer

The heart ejects as much blood as it receives; increased venous return increases preload and stroke volume.

Question 12

Which heart sound (S$$_1 or S$_2) is $$produced by the closure of the atrioventricular (AV) valves, and what is its typical description?

Accepted Answer

S$$_1$$; described as 'lub'

Question 13

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

Accepted Answer

Increased heart rate and force of contraction due to norepinephrine binding to $$\beta-$$adrenergic receptors

Question 14

Which of the following correctly matches the valve with its location and function?

Accepted Answer

Pulmonary valve: between right ventricle and pulmonary trunk; prevents backflow into ventricle

Question 15

Which of the following best explains why cardiac muscle is resistant to fatigue?

Accepted Answer

It has large mitochondria, is rich in myoglobin and glycogen, and depends almost exclusively on aerobic respiration.

Question 16

Which of the following ECG findings is most characteristic of ventricular fibrillation?

Accepted Answer

Chaotic, irregular electrical signals with no effective pumping action

Question 17

A patient with mitral valve prolapse is most likely to experience which of the following?

Accepted Answer

Bulging of both mitral valve cusps into the left atrium during ventricular contraction

Question 18

Which of the following is the correct sequence of electrical conduction through the heart?

Accepted Answer

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

Question 19

Which of the following would most likely increase afterload and reduce stroke volume?

Accepted Answer

Hypertension and atherosclerotic plaques

Question 20

During exercise, which physiological changes contribute to increased cardiac output?

Accepted Answer

Increased heart rate, increased stroke volume, and enhanced venous return due to muscular activity

Chapter 19: The Circulatory System – Heart (Anatomy & Physiology Study Notes)

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