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Module 7 - Autonomic Nervous System
Verified and Updated Questions and
Answers (100% Correct Answers)
the ANS controls
Answer: smooth muscle (e.g., muscles of blood vessels, hair follicles, and intrinsic
eye musculature), cardiac muscle, and glands (e.g., sweat, salivary, and lacrimal
glands).
The ANS carries out these functions via two subdivisions, the
Answer: sympathetic (SNS) and parasympathetic (PNS) nervous systems, which are in
many ways functional opposites.
In comparison to the somatic nervous system, the ANS has 3 distinct differences
Answer: 1. The somatic nervous system innervates skeletal muscle under voluntary
control, while the autonomic nervous system innervates organ systems and muscles
that are not under voluntary control.
2. In the somatic nervous system, a lower motor neuron projects directly from the
CNS to innervate skeletal muscle. In contrast, the ANS utilizes a two-neuron system
(preand postganglionic neurons) to reach target cells from the CNS.
Preganglionic neuron --> Postganglionic neuron --> Target cell
3. The somatic nervous system consists of large-diameter, thickly myelinated alpha
motor fibers. The preganglionic neurons of the ANS consist of small-diameter, lightly
myelinated fibers, while the postganglionic neurons consist of unmyelinated fibers.
As such, the conduction velocity and subsequent effects of the ANS are relatively
slow in comparison to the somatic nervous system.
Sympathetic system is generalized and tends to
Answer: "go off" as a whole.
The SNS preganglionic neurons arise from
Answer: cells in the intermediolateral region of the spinal cord gray matter from
levels T1 through L2 and project to postganglionic neurons
near the vertebral column; postganglionic neurons then project to target cells
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SNS: The preganglionic neurons are ______ and the postganglionic neurons are ______.
Answer: The preganglionic neurons are short and the postganglionic neurons are
long.
The PNS does not
Answer: "go off" as a whole; activities modulated independently when appropriate.
The PNS preganglionic neurons arise from
Answer: the brainstem (CNs III, VII, IX, X) and cells in the spinal cord gray matter
from levels S2-S4 and project to ganglia near the target organ; postganglionic
neurons then project to target cells.
PNS: The preganglionic neurons are _______ and the postganglionic neurons are
_______
Answer: The preganglionic neurons are long and the postganglionic neurons are
short
Both SNS & PNS use _________ as the preganglionic neurotransmitter
Answer: acetylcholine (ACh)
PNS uses ______ as the postganglionic neurotransmitter.
Answer: ACh
SNS uses__________ as the postganglionic neurotransmitter (except when ___________).
Answer: SNS uses norepinephrine (NE) as the postganglionic neurotransmitter
(except when innervating sweat glands, where ACh is utilized).
The control center of the sympathetic nervous system is in the _________. From there,
______________
Answer: The control center of the sympathetic nervous system is in the posterior
hypothalamus. From there, first-order neuron axons descend ipsilaterally through
the brainstem to the spinal cord
Upon reaching the spinal cord, sympathetic fibers
Answer: descend to and synapse on preganglionic (second-order) neurons in the
ipsilateral intermediolateral cell column, or IML, a distinguished group of neurons
located in the intermediate horn of the spinal cord from levels T1 through L2.
Preganglionic sympathetic neurons then project axons out of the spinal cord via the
Answer: ventral root
They travel only a short distance before they leave the ventral root via
Answer: white communicating rami (so named because these axons are myelinated
and appear white) to enter the paravertebral sympathetic chain ganglia - paired
Module 7 - Autonomic Nervous System
Verified and Updated Questions and
Answers (100% Correct Answers)
the ANS controls
Answer: smooth muscle (e.g., muscles of blood vessels, hair follicles, and intrinsic
eye musculature), cardiac muscle, and glands (e.g., sweat, salivary, and lacrimal
glands).
The ANS carries out these functions via two subdivisions, the
Answer: sympathetic (SNS) and parasympathetic (PNS) nervous systems, which are in
many ways functional opposites.
In comparison to the somatic nervous system, the ANS has 3 distinct differences
Answer: 1. The somatic nervous system innervates skeletal muscle under voluntary
control, while the autonomic nervous system innervates organ systems and muscles
that are not under voluntary control.
2. In the somatic nervous system, a lower motor neuron projects directly from the
CNS to innervate skeletal muscle. In contrast, the ANS utilizes a two-neuron system
(preand postganglionic neurons) to reach target cells from the CNS.
Preganglionic neuron --> Postganglionic neuron --> Target cell
3. The somatic nervous system consists of large-diameter, thickly myelinated alpha
motor fibers. The preganglionic neurons of the ANS consist of small-diameter, lightly
myelinated fibers, while the postganglionic neurons consist of unmyelinated fibers.
As such, the conduction velocity and subsequent effects of the ANS are relatively
slow in comparison to the somatic nervous system.
Sympathetic system is generalized and tends to
Answer: "go off" as a whole.
The SNS preganglionic neurons arise from
Answer: cells in the intermediolateral region of the spinal cord gray matter from
levels T1 through L2 and project to postganglionic neurons
near the vertebral column; postganglionic neurons then project to target cells
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SNS: The preganglionic neurons are ______ and the postganglionic neurons are ______.
Answer: The preganglionic neurons are short and the postganglionic neurons are
long.
The PNS does not
Answer: "go off" as a whole; activities modulated independently when appropriate.
The PNS preganglionic neurons arise from
Answer: the brainstem (CNs III, VII, IX, X) and cells in the spinal cord gray matter
from levels S2-S4 and project to ganglia near the target organ; postganglionic
neurons then project to target cells.
PNS: The preganglionic neurons are _______ and the postganglionic neurons are
_______
Answer: The preganglionic neurons are long and the postganglionic neurons are
short
Both SNS & PNS use _________ as the preganglionic neurotransmitter
Answer: acetylcholine (ACh)
PNS uses ______ as the postganglionic neurotransmitter.
Answer: ACh
SNS uses__________ as the postganglionic neurotransmitter (except when ___________).
Answer: SNS uses norepinephrine (NE) as the postganglionic neurotransmitter
(except when innervating sweat glands, where ACh is utilized).
The control center of the sympathetic nervous system is in the _________. From there,
______________
Answer: The control center of the sympathetic nervous system is in the posterior
hypothalamus. From there, first-order neuron axons descend ipsilaterally through
the brainstem to the spinal cord
Upon reaching the spinal cord, sympathetic fibers
Answer: descend to and synapse on preganglionic (second-order) neurons in the
ipsilateral intermediolateral cell column, or IML, a distinguished group of neurons
located in the intermediate horn of the spinal cord from levels T1 through L2.
Preganglionic sympathetic neurons then project axons out of the spinal cord via the
Answer: ventral root
They travel only a short distance before they leave the ventral root via
Answer: white communicating rami (so named because these axons are myelinated
and appear white) to enter the paravertebral sympathetic chain ganglia - paired
