Question 1

Which of the following best describes the difference between the somatic and autonomic nervous systems in terms of their efferent pathways?

Accepted Answer

The somatic nervous system uses a single myelinated neuron to reach skeletal muscle, while the autonomic nervous system uses two neurons (preganglionic and postganglionic) to reach visceral effectors.

Question 2

A patient presents with exaggerated heart rate and blood pressure after a spinal cord injury that severed autonomic nerves. What is the physiological explanation for this response?

Accepted Answer

Loss of autonomic input causes denervation hypersensitivity, leading to exaggerated responses in cardiac muscle.

Question 3

Which neurotransmitter is always released by preganglionic neurons in both the sympathetic and parasympathetic divisions of the ANS?

Accepted Answer

Acetylcholine (ACh)

Question 4

Which of the following is a correct statement about the sympathetic division's anatomical organization?

Accepted Answer

It has short preganglionic and long postganglionic fibers, with cell bodies in the thoracic and lumbar regions.

Question 5

During a stressful event, which of the following physiological changes is most likely due to increased sympathetic activity?

Accepted Answer

Increased respiratory rate and dilation of respiratory passageways

Question 6

Which neurotransmitter is primarily released by sympathetic postganglionic neurons at most target organs?

Accepted Answer

Norepinephrine (NE)

Question 7

A toxin that binds to muscarinic receptors would most likely affect which of the following?

Accepted Answer

Cardiac muscle, smooth muscle, and gland cells with cholinergic innervation

Question 8

Which of the following best explains why sympathetic effects tend to last longer than parasympathetic effects?

Accepted Answer

Norepinephrine released by sympathetic fibers can be reabsorbed, diffuse, or enter the bloodstream, while acetylcholine from parasympathetic fibers is quickly broken down at the synapse.

Question 9

Which of the following is an example of dual innervation producing antagonistic effects?

Accepted Answer

Sympathetic stimulation increases heart rate while parasympathetic stimulation decreases heart rate.

Question 10

Which receptor type is always excitatory when acetylcholine binds to it?

Accepted Answer

Nicotinic receptor

Question 11

A patient is given a beta-blocker to treat hypertension. What is the mechanism of action of this drug?

Accepted Answer

It blocks beta-adrenergic receptors, reducing the effects of epinephrine and norepinephrine on the heart and blood vessels.

Question 12

Which division of the ANS is responsible for stimulating lipolysis in adipocytes, and through which receptor?

Accepted Answer

Sympathetic division via beta-3 adrenergic receptors

Question 13

Which of the following is true regarding the enteric nervous system?

Accepted Answer

It is composed of neurons found in the walls of the digestive tract and regulates motility and secretion independently, but is also influenced by sympathetic and parasympathetic systems.

Question 14

Which of the following best describes the effect of alpha-1 adrenergic receptor activation?

Accepted Answer

It releases intracellular calcium ions, causing constriction of smooth muscle in blood vessels.

Question 15

Which cranial nerve carries approximately 75% of all parasympathetic outflow?

Accepted Answer

X (vagus)

Question 16

Which of the following is NOT a response to increased parasympathetic activity?

Accepted Answer

Increased heart rate and blood pressure

Question 17

Which part of the brain contains nuclei for primitive functions such as hunger, thirst, and sex, and is a major control center for the ANS?

Accepted Answer

Hypothalamus

Question 18

A drug that acts as a sympathomimetic would most likely produce which of the following effects?

Accepted Answer

Stimulation of beta-adrenergic receptors, leading to increased heart rate and bronchodilation

Question 19

Which of the following equations correctly represents the relationship between sympathetic tone and blood vessel diameter?

Accepted Answer

$$D \propto \frac{1}{F}$$, where $$D is $$vessel diameter and $$F is $$sympathetic firing frequency

Question 20

Which of the following is a correct statement about the effect of acetylcholine on muscarinic receptors in different organs?

Accepted Answer

ACh can excite intestinal smooth muscle but inhibit cardiac muscle, depending on the receptor subtype.

Study Notes: The Autonomic Nervous System (Chapter 15, BSC 2085: Anatomy & Physiology I)

Study Guide - Practice Questions

Study Guide - Flashcards