Question 1

Which of the following best describes the effect of the sympathetic nervous system on heart rate?

Accepted Answer

It increases heart rate by releasing norepinephrine at the SA node.

Question 2

Which nerve is primarily responsible for parasympathetic modulation of heart rate?

Accepted Answer

Vagus nerve

Question 3

A patient is experiencing tachycardia due to increased sympathetic activity. Which neurotransmitter is most likely elevated at the heart?

Accepted Answer

Norepinephrine

Question 4

If the vagus nerve is damaged, what is the most likely effect on heart rate?

Accepted Answer

Heart rate will increase due to loss of parasympathetic inhibition.

Question 5

Which of the following equations best represents the relationship between cardiac output, heart rate, and stroke volume?

Accepted Answer

$$CO = HR 	imes SV$$

Question 6

During a stressful event, which pathway is activated to increase heart rate?

Accepted Answer

Sympathetic pathway via the cardiac accelerator nerves

Question 7

Which of the following is a direct effect of parasympathetic stimulation on the SA node?

Accepted Answer

Decreased rate of depolarization

Question 8

A patient with a heart transplant lacks vagal innervation. What is the expected resting heart rate compared to a normal individual?

Accepted Answer

Higher than normal due to lack of parasympathetic inhibition

Question 9

Which of the following nerves carries sympathetic fibers to the heart?

Accepted Answer

Cardiac accelerator nerves

Question 10

If both sympathetic and parasympathetic inputs to the heart are blocked, what would happen to the heart rate?

Accepted Answer

It would be determined by the intrinsic rate of the SA node.

Question 11

Which neurotransmitter is released by the vagus nerve at the heart?

Accepted Answer

Acetylcholine

Question 12

A patient is given a drug that blocks muscarinic receptors in the heart. What is the expected effect?

Accepted Answer

Increased heart rate due to blocked parasympathetic activity

Question 13

Which of the following best explains the role of the cardiac accelerator nerves?

Accepted Answer

They increase heart rate by releasing norepinephrine.

Question 14

Which pathway is most active during sleep to maintain a lower heart rate?

Accepted Answer

Parasympathetic pathway via the vagus nerve

Question 15

A patient with a lesion in the medulla oblongata affecting the vagal nuclei would most likely experience which of the following?

Accepted Answer

Tachycardia due to decreased parasympathetic output

Autonomic Regulation of Heart Rate: Sympathetic and Parasympathetic Pathways

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