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Through direct neural stimulation, the sympathetic division promotes many metabolic effects via hormone release.
Cranial nerves VII, IX, and X contain postganglionic fibers of the parasympathetic nervous system.
In contrast to the parasympathetic division, the sympathetic division has numerous ganglionic neurons in the gray matter of the spinal cord.
The blood vessels of the skin are one of the few areas of the body where the vessels are innervated by both the sympathetic and parasympathetic divisions.
Since the ANS is a visceral motor system, afferent pathways are of no importance and actually are rarely found.
The autonomic nervous system may cause activation or inhibition, depending on the division that is active and the target that is affected.
Acetylcholine is the substance released by the axonal endings of the somatic efferent fibers and by the parasympathetic nerve fiber endings.
Since many of the same cardiac cells are innervated by both parasympathetic and sympathetic fibers, the influence of the two divisions on the heart is synergistic.
The secretions of the adrenal medulla act to supplement the effects of ________.
In contrast to the somatic nervous system, the autonomic nervous system ________.
has two efferent neurons
Preparing the body for the ʺfight-or-flightʺ response is the role of the ________.
sympathetic nervous system
The parasympathetic nervous system is characterized by peripheral ganglia near the ________.
organs and by short postganglionic fibers
A drug that might be used specifically to reduce heart rate in cardiac patients could be ________.
Cardiovascular effects of the sympathetic division include all except ________.
dilation of the blood vessels serving the skin and digestive viscera
The ʺresting and digestingʺ division of the autonomic nervous system is the ________.
Control of temperature, endocrine activity, and thirst are functions associated with the ________.
Which of these effectors is not directly controlled by the autonomic nervous system?
The site of origin of the preganglionic fibers of the parasympathetic nervous system is the ________.
brain stem and the sacral region of the cord
Sympathetic responses generally are widespread because ________.
single preganglionic axons make multiple synapses with ganglionic neurons
The parasympathetic fibers of the ________ nerves innervate smooth muscles of the lens of the eye, the muscles that cause the eye to bulge to accommodate close vision.
Fibers that enter and leave the sympathetic chain without synapsing form structures called ________.
The autonomic nervous system ________.
is directly controlled by the reticular formation of the brain stem
The mass reflex reaction ________.
represents a return of reflex activity with no controls from higher centers
In congenital megacolon (Hirschsprung's disease) ________.
the distal portion of the large intestine fails to develop parasympathetic innervation
In aging, autonomic inefficiency is often due to ________.
clogging of preganglionic axon terminals with filaments
Sympathetic fibers leave the spinal cord in the ________.
thoracolumbar region, and the postganglionic fibers secrete norepinephrine
Sympathetic division stimulation causes ________.
increased blood glucose, decreased GI peristalsis, and increased heart rate and blood pressure
All preganglionic axons of the autonomic nervous system release ________.
the same transmitter as the one released by parasympathetic postganglionic axons
The only sympathetic preganglionic neuron to go directly to an organ is one branch of the ________ splanchnic nerve.
The parasympathetic division uses only ________ as a neurotransmitter in the ganglionic neurons.
How are the sympathetic and parasympathetic divisions different?
1. They have unique origin sites.
2. They have different lengths of pre- and postganglionic axons.
3. Their ganglia are located in different areas.
In what ways are the autonomic nervous system and the somatic nervous system different?
1. The autonomic is a two-neuron system; the somatic uses one.
2. The autonomic uses smaller neuron fibers (type B or C); the somatic generally uses the type A fibers.
3. The autonomic is mostly involuntary and automatic; the somatic is voluntary.
4. The autonomic uses several neurotransmitters and many receptor types; the somatic uses only one.
5. The autonomic is a slow system; the somatic is a fast system.
6. The autonomic has opposing forces to regulate the body; the somatic does not.
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