Q: Given an end-diastolic volume (EDV) of 130 mL and an end-systolic volume (ESV) of 60 mL, what is the stroke volume (SV)? Use the formula $$SV = EDV - ESV.$$

$$SV = 130\ \text{mL} - 60\ \text{mL} = 70\ \text{mL}$$

Q: A patient has a heart rate (HR) of 80 beats per minute and a stroke volume (SV) of 75 mL. What is the cardiac output (CO)? Use the formula $$CO = HR \times SV.$$

$$CO = 80 \times 75 = 6000\ \text{mL/min}$$

Question 1

Which of the following best defines stroke volume (SV)?

Accepted Answer

The amount of blood ejected by a ventricle with each heartbeat.

Question 2

Given an end-diastolic volume (EDV) of 130 mL and an end-systolic volume (ESV) of 60 mL, what is the stroke volume (SV)? Use the formula $$SV = EDV - ESV.$$

Accepted Answer

$$SV = 130\ 	ext{mL} - 60\ 	ext{mL} = 70\ 	ext{mL}$$

Question 3

A patient has a heart rate (HR) of 80 beats per minute and a stroke volume (SV) of 75 mL. What is the cardiac output (CO)? Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 80 	imes 75 = 6000\ 	ext{mL/min}$$

Question 4

Which of the following statements about cardiac output in the right and left ventricles is correct?

Accepted Answer

Cardiac output is normally equal in both the right and left ventricles.

Question 5

Which of the following best describes preload?

Accepted Answer

The degree of stretch of the ventricular muscle fibers at the end of diastole.

Question 6

How does increased contractility affect stroke volume, assuming preload and afterload remain constant?

Accepted Answer

It increases stroke volume.

Question 7

Afterload is best defined as:

Accepted Answer

The resistance the ventricles must overcome to eject blood.

Question 8

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

Accepted Answer

Decreased stroke volume.

Question 9

Which of the following best describes the role of the sympathetic nervous system (SNS) in cardiac function?

Accepted Answer

It increases heart rate and contractility.

Question 10

Which cells in the heart are primarily innervated by the parasympathetic nervous system (PNS)?

Accepted Answer

Sinoatrial (SA) and atrioventricular (AV) nodes.

Question 11

A patient is experiencing bradycardia (slow heart rate) due to increased vagal tone. Which branch of the autonomic nervous system is responsible?

Accepted Answer

Parasympathetic nervous system.

Question 12

Which of the following is a correct pathway for sympathetic innervation of the heart?

Accepted Answer

Preganglionic neurons from the spinal cord synapse in the sympathetic chain ganglia, then postganglionic fibers innervate the SA node.

Question 13

Which neurotransmitter is released by sympathetic postganglionic fibers at the heart, and what is its effect?

Accepted Answer

Norepinephrine; increases heart rate and contractility.

Question 14

Which of the following best describes the effect of parasympathetic stimulation on the heart?

Accepted Answer

Decreases heart rate but has little effect on ventricular contractility.

Question 15

Baroreceptors in the carotid sinus and aortic arch detect changes in blood pressure. Which reflex center integrates this information to regulate heart rate?

Accepted Answer

Medullary cardiovascular center.

Question 16

A patient with damage to the vagus nerve would most likely experience which of the following changes in cardiac function?

Accepted Answer

Increased heart rate due to loss of parasympathetic inhibition.

Question 17

Which of the following best describes the effect of increased sympathetic stimulation on cardiac output?

Accepted Answer

It increases cardiac output by increasing both heart rate and stroke volume.

Question 18

Which of the following is a correct statement about the autonomic innervation of the heart?

Accepted Answer

Parasympathetic fibers primarily innervate the SA and AV nodes, while sympathetic fibers innervate both nodes and ventricular myocardium.

Question 19

A patient is given a drug that blocks beta-adrenergic receptors in the heart. What is the expected effect on cardiac output during exercise?

Accepted Answer

Decreased cardiac output due to reduced heart rate and contractility.

Question 20

Which of the following scenarios best illustrates the Frank-Starling law of the heart?

Accepted Answer

An increase in venous return leads to increased end-diastolic volume, which increases stroke volume.

Cardiac Physiology: Stroke Volume, Cardiac Output, and Autonomic Regulation

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