Chapter 15 - The Autonomic Nervous System

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Study guide for Chapter 15 in Dr. K's class


regulates activity of smooth muscle, cardiac muscle and certain glands


receives input from limbic system and other regions of the cerebrum

somatic nervous system

The ________ contains both sensory and motor neurons.

somatic sensory neurons

The __________ receive input from receptors of the special and somatic senses.

somatic motor neurons

___________ innervate skeletal muscle to produce conscious, voluntary movements.


The effect of a motor neuron is always ___________.

autonomic nervous system

The _________________ contains both autonomic sensory and motor neurons.


The ________ also receives sensory input from somatic senses and special sensory neurons.

autonomic motor neurons

The ________ regulate visceral activities by either increasing (exciting) or decreasing (inhibiting) ongoing activities of cardia muscle, smooth muscle, and glands.


All somatic motor pathways consist of a _______motor neuron.


Autonomic motor pathways consists of ______ motor neurons in series.

CNS, myelinated, autonomic ganglion

The first autonomic neuron motor has its cell body in the _____ and its _______ axon extends to a ___________.


a collection neuronal cell bodies in the PNS.

autonomic ganglion, nonmyelinated, effector

The second autonomic motor neuron has its cell body in an _______, its ________, extends to an_________.

sympathetic, parasympathetic

an increased rate of nerve impulses from the __________ division increases heart rate, and an increased rate of nerve impulses from the __________division decreases heart rate.

preganglionic neuron

its cell body is in the brain or spinal cord, and its axon exits the CNS as part of a cranial or spinal nerve.

postganglionic neuron

lies entirely outside the CNS, its cell body and dendrites are located in an autonomic ganglion where it forms synapses with on or more preganglionic axons.

ACh, Norephinephrine

Cholinergic neurons release ________ and adnergic neurons release ________

fight or flight, rest and digest

Because of he location of the preganglionic cell bodies, the sympatheric division of the ANS is aslo called the _______division, the parasympathetic division is also called the _______ division.


Which of the following is not an effector (target) of autonomic nervous system (ANS) motor neurons?
a. cardiac muscle
b. exocrine glands
c. skeletal muscle
d. endocrine glands
e. smooth muscle


Somatic motor neurons have cell bodies located ______the CNS that send axons to ______; usually
under ______control.
a. outside; skeletal muscle; involuntary
b. inside; the viscera; voluntary
c. outside; the viscera; involuntary
d. inside; skeletal muscle; voluntary
e. outside; the viscera; voluntary


Which of the following statements does not describe denervation hypersensitivity?
a. autonomic target tissues become more sensitive than normal to stimulating agents
b. skeletal muscle effectors enter a state of flaccid paralysis and atrophy
c. can result from severing (cutting) autonomic motor neurons
d. an example is restoring the secretion of acid from the stomach following vagotomy (severing the
Vagus nerve)


true or false
Autonomic motor nerves innervate organs whose functions are not usually under voluntary control.


true or false
The word viscera refers to the organs located within the body cavities.


true or false
Unlike somatic motor neurons, autonomic motor neurons always involve two neurons in the efferent

f outside

true or false
A ganglion is defined as a collection of cell bodies inside the CNS (brain and spinal cord).

f autonomic

true or false
Ganglia are an integral part of the somatic motor pathway


true or false
Cardiac muscle (the heart) and many smooth muscles can contract rhythmically even in the absence of
autonomic nerve stimulation.


true or false
Unlike somatic motor neurons that always cause stimulation of skeletal muscle effectors, some autonomic
nerves release neurotransmitter substances that inhibit the activity of their effectors.


Which statement regarding autonomic sympathetic neurons is false?
a. They are usually activated as a single unit (mass activation).
b. They emerge from the brain and sacral regions.
c. They form white and gray rami communicantes fibers.
d. They may have ganglia located along the spinal cord


Which of the following ganglia is not a collateral (prevertebral) ganglion?
a. celiac
b. superior mesenteric
c. inferior mesenteric
d. cervical


Which system is not served by postganglionic fibers that arise from the collateral (prevertebral) ganglia?
a. respiratory
b. digestive
c. urinary
d. reproductive
e. All of these systems are served by these postganglionic fibers


Which of the following statements about parasympathetic neurons is false?
a. Like sympathetics, they travel within spinal nerves.
b. They synapse in terminal ganglia, either next to or within the organs innervated.
c. They originate in the brain or sacral spinal cord regions (the craniosacral division).
d. Postganglionic fibers are usually shorter than those of sympathetic neurons.
e. They send preganglionic fibers to the visceral organs, such as the heart, lungs, esophagus, intestine,
among others.


true or false
Both sympathetic and parasympathetic neurons have preganglionic cell bodies located inside the CNS
and postganglionic cell bodies located outside the CNS


true or false
Preganglionic sympathetic neurons are myelinated, and thus, called white rami communicantes, while
postganglionic sympathetic fibers are unmyelinated, and therefore, known as the gray rami

f divergence

true or false
The convergence of impulses from the spinal cord to the ganglia and the divergence of impulses within
the ganglia usually result in the mass activation of almost all postganglionic fibers as
a unit.

f medulla

true or false
The cortex of the adrenal gland is a modified sympathetic ganglion


true or false
Neurons whose cell bodies originate in the medulla oblongata and whose axons serve as cranial nerves
would be classified as parasympathetic


true or false
Sympathetic neurons show great divergence from preganglionic to postganglionic fibers, whereas
parasympathetic neurons diverge only a little.


Which neuron does not release acetylcholine (ACh) as a neurotransmitter?
a. preganglionic sympathetic fibers
b. postganglionic sympathetic fibers
c. preganglionic parasympathetic fibers
d. postganglionic parasympathetic fibers


Catecholamines are substances derived from the amino acid, tyrosine, and include all of the following
a. acetylcholine (ACh).
b. epinephrine.
c. dopamine.
d. norepinephrine


Which of the following is not a ß-adrenergic response?
a. slowing down (relaxation) of the digestive tract muscular motility, such as peristalsis
b. opening of the airways or bronchioles in the lung
c. increasing the force and rate of the heart beat
d. dilating the smooth muscle of the skin and splanchnic blood vessels
e. relaxing the smooth muscle wall of the urinary bladder


The drug that aids the suffering of asthmatics by serving as a ß2 agonist to dilate the airways of the lung,
a. terbutaline.
b. atenolol.
c. phenylephrine.
d. clonidine.


Which statement about muscarinic receptors is false?
a. They are not found in autonomic ganglia or at the neuromuscular junctions of skeletal muscle fibers.
b. They are stimulated by extracts from poisonous mushrooms.
c. They are subtypes of adrenergic receptors.
d. They are not affected by the drug, curare that specifically blocks nicotinic receptors.
e. They can be found on the target organs of specific postganglionic parasympathetic fibers.


Which of the following molecules is not a proposed neurotransmitter of the select group of
"nonadrenergic noncholinergic" postganglionic autonomic axons?
a. adenosine triphosphate (ATP)
b. gamma aminobutyric acid (GABA)
c. vasoactive intestinal peptide (VIP)
d. nitric oxide (NO)


The separate effects of sympathetic and parasympathetic innervation of the pacemaker region of the heart
can best be described as
a. antagonistic.
b. complementary.
c. cooperative (synergistic)


The effects of sympathetic and parasympathetic innervation on the urinary and reproductive systems are
a. antagonistic.
b. complementary.
c. cooperative (synergistic).


The effects of sympathetic and parasympathetic stimulation on the salivary gland secretion are
a. antagonistic.
b. complementary.
c. cooperative (synergistic).


Which of the following target tissues is (are) innervated only by the sympathetic neurons?
a. adrenal medulla
b. arrector pili muscle
c. sweat glands
d. most blood vessels
e. All of these are only innervated by sympathetic neurons.


That brain stem region that directly controls many activities of the autonomic nervous system (ANS), is
a. medulla oblongata.
b. pituitary gland.
c. cerebellum.
d. hypothalamus.
e. basal ganglia.


Which system does not have its control center in the medulla?
a. cardiovascular system
b. pulmonary system
c. urinary system
d. reproductive system
e. immune system


The hypothalamus does not contain the control center for the homeostatic regulation of
a. body temperature.
b. various emotional states.
c. hunger.
d. breathing.
e. thirst.

f sympathetic

true or false
The term "fight or flight" is used to describe the mass activation of the parasympathetic system that
prepares the body for intense physical activity in emergency situations.


true or false
Cocaine is considered a sympathomimetic drug - a drug that mimics or promotes the effects of
sympathetic nerve activity through the action of norepinephrine.


true or false
Sympathetic and parasympathetic neurons usually release different neurotransmitters from their
respective postganglionic neuron axons.


true or false
Those sympathetic postganglionic neurons activating blood vessels in skeletal muscle and in sweat glands
are unique in their release of acetylcholine (ACh) instead of norepinephrine (NE).


true or false
Adrenergic stimulation by epinephrine, usually secreted by the adrenal medulla, and by norepinephrine,
secreted from sympathetic nerve endings, can produce both excitatory and inhibitory effects.


true or false
The autonomic neurons are unique in that they form synapses en passant ("synapses in passing") as
neurotransmitters are released from numerous swellings or varicosities as they pass through their target

f beta

true or false
The two major subtypes of alpha-receptors produce their effects by stimulating increases in the
production of the second messenger, cyclic AMP (cAMP), within the target cell cytoplasm.


true or false
The response of a target cell when norepinephrine binds to α
receptors results in a rise in intracellular 
calcium (Ca
) concentration that serves as a "second messenger" molecule.


true or false
The physiology of α2-adrenergic receptors is complex because these receptors are mainly located on the
presynaptic axon terminals (decreasing NE release), yet are found on the postsynaptic membrane of
vascular smooth muscle cells, resulting in complicated influence on blood pressure.


true or false
When epinephrine and norepinephrine bind to adrenergic receptors in the ANS a group of membraneassociated G-proteins dissociate into subunits, and thereby activate their respective target cells.


true or false
Stimulation of alpha-adrenergic receptors located on smooth muscle fibers in the walls of blood vessels
almost always results in muscle contraction and vasoconstriction.

f they are excitatory only

true or false
The activation of all somatic motor neurons or preganglionic autonomic neurons results in cholinergic
effects that can be both excitatory and inhibitory.


true or false
Both nicotinic and muscarinic receptors bind with and respond to the neurotransmitter, acetylcholine

f nicotine

true or false
Cholinergic receptors of the muscarinic type are ligand-gated ion channels — that is, binding by ACh
causes the faster entry of Na
that always results in depolarization and excitation of the target cell.


true or false
Five different subtypes of muscarinic ACh receptors (designated with the letter "M," followed by a
number in subscript) have been identified.


true or false
The responses of muscarinic receptors on target cells that are activated by the binding of ACh is mediated
by second messenger systems, and is therefore not mediated by ligand-gated ion channels.


true or false
Nitric oxide (NO) is one of many nonadrenergic, noncholinergic paracrine regulator molecules that
produce relaxation of smooth muscles in many organs and in blood vessels.

f decrease

true or false
Parasympathetic neuron stimulation of the pacemaker region of the heart increases the heart rate.


true or false
In the digestive system, activation of parasympathetic neurons increases intestinal movements and
stimulates intestinal secretions.


true or false
Increased sympathetic neuron activity to smooth muscle fibers around blood vessels of the skin
(cutaneous) causes vasoconstriction, whereas cutaneous vasodilation results when sympathetic nerve
activity is decreased.


true or false
Cooling of the body can be accomplished by sweat glands along the trunk that secrete both a watery
sweat that evaporates and a chemical called bradykinin, that dilates surface blood vessels to help radiate


true or false
The Vagus nerve (cranial nerve X) is a mixed nerve, containing both sensory and motor neuron fibers.


true or false
Thermoregulation, the regulation of heat gain or loss by the body, is accomplished without the direct
involvement of the parasympathetic nervous system.

f limbic system

true or false
Blushing, pallor, fainting, breaking out in a cold sweat, a racing heartbeat, and "butterflies in the
stomach", are only some of the many visceral reactions that accompany emotional activation of the

efferent, brain, spinal cord, cell bodies, ganglia

Autonomic neuron axons are always motor or __________, originating in the __________ or __________ as
preganglionic neurons. Postganglionic neurons originate from collections of __________ outside the CNS,
known as __________.

effector, smooth muscle, cardiac muscle, glands

The three target or __________ cells at the end of autonomic neurons are __________ __________,
__________ __________, and __________.

denervation hypersensitivity, thoracic, lumbar, brain, sacral

Severing or cutting autonomic neurons results in an increase in responsiveness at the target cell. This
characteristic of autonomic neurons is called __________. Preganglionic sympathetic neurons emerge from the
__________ and __________ levels of the spinal cord, whereas preganglionic parasympathetic fibers originate
in the __________ and __________ levels of the spinal cord.

paravertebral, collateral, urinary, reproductive, adrenal

Cell bodies of postganglionic sympathetic neurons are located in ganglia called the sympathetic or __________
ganglia; the __________ ganglia (which include the celiac and mesenteric) innervate organs of the digestive,
__________, and __________ systems. Modified sympathetic ganglion cells are located directly in the medulla
of the __________ gland.

pre-. parasympathetc, short, within

Many cranial nerves are __________ (pre-/post-) ganglionic __________ (sympathetic/parasympathetic)
neurons with __________ (long/short) postganglionic neurons because the ganglia are located close to or
__________ the target cells.

NE, sympathetic, adrenergic

"Fight or flight" results from the release of the neurotransmitter __________ from postganglionic __________
(sympathetic/parasympathetic) neurons—effects called __________.

parasympathetic, ACh, cholinergic, sweat glands, blood vessels

All preganglionic fibers and all postganglionic fibers that carry information themed as "repast and repose" are
__________ (sympathetic/parasympathetic), release only the neurotransmitter __________; and their effects are
called _________________. Hint: Sympathetic fibers that innervate __________ __________ and those that
innervate __________ __________ in skeletal muscles are cholinergic!

alpha, beta, adrenergic

Norepinephrine binds to two groups of receptor proteins, known as __________ and __________, with two
subtypes for each (1 and 2), which produce __________ (adrenergic/cholinergic) effects in various organs of the

dual, antagonistic, complementary, cooperative

In organs stimulated by both sympathetic and parasympathetic neurons (__________ innervation), the actions
between these two types of neurons will be __________, __________, or __________.

medulla oblongata, hypothalamus

The two most important regions of the brain directly responsible for the control of autonomic nervous system
activity are the __________ __________ located in the brain stem and the higher brain region called the

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