Chapter 11 Review Questions

Question 1

Name the two efferent divisions of the peripheral nervous system. What type of effectors does each control?

Answer 1

Somatic motor—skeletal muscles. Autonomic—smooth and cardiac muscle, glands, some adipose tissue.

Question 2

The autonomic nervous system is sometimes called the nervous system. Why is this an appropriate name? List some functions controlled by the autonomic nervous system.

Answer 2

Visceral nervous system because it controls internal organs (viscera) and functions such as heart rate and digestion.

Question 3

What are the two branches of the autonomic nervous system? How are these branches distinguished from each other anatomically and physiologically?

Answer 3

Sympathetic and parasympathetic divisions. Sympathetic neurons exit the spinal cord in the thoracic and lumbar regions; ganglia are close to the spinal cord. Parasympathetic exit from the brain stem or sacral region; ganglia on or close to their targets. Sympathetic—fight-or-flight; parasympathetic—rest-and-digest

Question 4

Which neurosecretory endocrine gland is closely allied to the sympathetic branch?

Answer 4

adrenal medulla

Question 5

Neurons that secrete acetylcholine are described as neurons, whereas those that secrete norepinephrine are called either or neurons.

Answer 5

Cholinergic—acetylcholine, adrenergic or noradrenergic— norepinephrine.

Question 6

List four things that can happen to autonomic neurotransmitters after they are released into a synapse.

Answer 6

Diffuse away from the synapse, broken down by enzymes in the synapse, taken back into the presynaptic neuron, or bind to a membrane receptor.

Question 7

The main enzyme responsible for catecholamine degradation is , abbreviated as .

Answer 7

monoamine oxidase, MAO

Question 8

What is acetylcholinesterase? Describe its action.

Answer 8

enzyme that breaks down ACh

Question 9

Somatic motor pathways
a. are excitatory or inhibitory?
b. are composed of a single neuron or a preganglionic and a postganglionic neuron?
c. synapse with glands or with smooth, cardiac, or skeletal muscle?

Answer 9

(a) excitatory, (b) single neuron, (c) synapse with skeletal muscle

Question 10

What kind of receptor is found on the postsynaptic cell in a neuromuscular junction?

Answer 10

nicotinic cholinergic receptors

Question 11

What is the advantage of divergence of neural pathways in the autonomic nervous system?

Answer 11

Divergence allows one signal to affect multiple targets.

Question 12

Compare and contrast:
a. neuroeffector junctions and neuromuscular junctions
b. alpha, beta, muscarinic, and nicotinic receptors. Describe where each is found and the ligands that bind to them.

Answer 12

a. Neuroeffector junction—distal ends of autonomic axons, anywhere there is a varicosity. Neuromuscular junction—axon terminals of the somatic motor neuron.

b. Alpha and beta adrenergic; nicotinic and muscarinic cholinergic. Nicotinic—on skeletal muscle and postganglionic autonomic neurons.

Question 13

Compare and contrast
a. autonomic ganglia and CNS nuclei
b. the adrenal medulla and the
posterior pituitary gland
c. axon terminals and varicosities

Answer 13

(a) Autonomic ganglia—nerve cell bodies of postganglionic autonomic neurons. CNS nuclei—nerve cell bodies in the brain and spinal cord. (b) Both have true endocrine tissue and neuroendocrine tissue. (c) Boutons—ends of axons; varicosities—strung out along the ends of autonomic neurons.

Question 14

Create a concept map comparing the somatic motor division and the sympathetic and parasympathetic branches of the autonomic division. You may add terms.
acetylcholine
alpha receptor
beta receptor
cholinergic receptor
endocrine gland
ganglion
nicotinic receptor
one-neuron pathway
skeletal muscle
somatic motor division
two-neuron pathway
adipose tissue
autonomic division
cardiac muscle
efferent division
exocrine gland
muscarinic receptor
norepinephrine
parasympathetic branch
smooth muscle
sympathetic branch

Question 15

If a target cell’s receptor is (use items in left column), the neuron(s) releasing neurotransmitter onto the receptor must be (use all appropriate items from the right column)

A. nicotinic cholinergic
B. adrenergic α
C.muscarinic cholinergic
D. adrenergic β

1. somatic motor neuron
2. autonomic preganglionic neuron
3. sympathetic postganglionic neuron
4. parasympathetic postganglionic neuron

Answer 15

A. 1,2
B. 3
C. 4
D. 3

Question 16

Ganglia contain the cell bodies of (choose all that apply)
a. somatic motor neurons
b. preganglionic autonomic neurons
c. interneurons
d. postganglionic autonomic neurons
e. sensory neurons

Answer 16

d, e

Question 17

If nicotinic receptor channels allow both and to flow through, why does influx exceed efflux?(Hint: p. 153.)

Answer 17

The electrochemical gradient for Na+ is greater than that for K+.

Question 18

You have discovered a neuron that innervates an endocrine cell in the intestine. To learn more about this neuron, you place a marker substance at the endocrine cell synapse. The marker is taken into the neuron and transported in a vesicle by retrograde axonal transport to the nerve cell body.
a. By what process is the marker probably taken into the axon terminal?
b. The nerve cell body is found in a ganglion very close to the endocrine cell. To which branch of the peripheral nervous system does the neuron probably belong? (Be as specific as you can.)
c. Which neurotransmitter do you predict will be secreted by the neuron onto the endocrine cell?

Answer 18

(a) endocytosis, (b) parasympathetic autonomic, (c) acetylcholine

Question 19

The Huaorani Indians of South America use blowguns to shoot darts poisoned with curare at monkeys. Curare is a plant toxin that binds to and inactivates nicotinic ACh receptors. What happens to a monkey struck by one of these darts?

Answer 19

Skeletal muscles would become paralyzed. Monkey could not flee.

Question 20

The U.S. Centers for Disease Control and Prevention (CDC) conduct biennial Youth Risk Behavior Surveys (YRBS) in which they ask high school students to self-report risky behaviors such as alcohol consumption and smoking. The graphs that follow were created from data in the report on cigarette smoking among American high school students. Current smoking is defined as smoking cigarettes on at least one day in the 30 days preceding the survey. (Morbidity and Mortality Weekly Report 65(6): 79, June 10, 2016. www.cdc.gov/mmwr/)
a. What can you say about cigarette smoking among high school students in the period from 1991 to 2015?
b. Which high school students are most likely to be smokers? Least likely to be smokers?

Answer 20

Increased 1991-1997, then began to decrease. Declining slowly from 2003 on. (b) Most likely—white and Hispanic males and white females. Least likely—black females.