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41 terms

Sympathetic nervous system

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preganglionic neurons
are located in the lateral gray horns of the spinal cord from the first thoracic to the second or third lumbar levels of the spinal cord (thoracolumbar outflow)
preganglionic axons
traverse the ventral roots of the spinal nerves and enter the ventral ramus of a spinal nerve
white communicating ramus
myelinated preganglionic axons then exit the ventral ramus as a bundle referred to as this:
sympathetic trunk
myelinated preganglionic axons then exit the ventral ramus as a bundle of white communicating ramus and enter this
paravertebral ganglia
the sympathetic trunks consist of sympathetic ganglia (referred to as this) connected by bundles of intervening preganglionic sympathetic fibers, the structure appearing like beads on a string
ganglion impar
each trunk extends from a level of the first cervical vertebra to the tip of the coccyx where they are connected to a slight enlargement that is referred to as this
sympathetic trunk
each one of these consists of three cervical sympathetic ganglia (superior, middle, inferior) eleven or twelve thoracic ganglia, four or five lumbar ganglia, and five or less sacrococcygeal ganglia.
stellate ganglion
inferior cervical ganglion is often fused with the first thoracic ganglion forming this
preganglionic fibers
when these originate in the thoracolumbar portions of the spinal cord, after entering the sympathetic trunks, they do many things
gray communicating rami
consist of unmyelinated postganglionic sympathetic fibers and are found at ALL levels
white communicating rami
are only found from T1 to L2 or L3
preganglionic fibers
pass thru the sympathetic trunk ganglia WITHOUT synapsing and travel via the thoracic, lumbar, and sacral splanchnic nerves to the prevertebral (collateral) ganglia
preganglionic fibers
pass thru all of the ganglia (paravertebral and prevertebral) and synapse with chromaffin cells of the adrenal medulla (modified sympathetic ganglion cells)
gray communicating rami
post ganglionic sympathetic fibers destined for distribution within the beck, body wall, and limbs, enter all 31 sets of spinal nerves. They pass from the sympathetic trunk ganglia (paravertebral ganglia) to adjacent ventral rami of spinal nerves via these
post ganglionic sympathetic fibers
enter all branches of all 31 sets of spinal nerves including the dorsal rami (for the back)
post ganglionic sympathetic fibers
enter all branches of all 31 sets of spinal nerves including the dorsal rami (for the back) to stimulate contraction of blood vessels (vasomotor fibers)
post ganglionic sympathetic fibers
enter all branches of all 31 sets of spinal nerves including the dorsal rami (for the back) to stimulate contraction of arrector pili muscles associated with hair follicles (pilomotor fibers resulting in "goose bumps"
post ganglionic sympathetic fibers
enter all branches of all 31 sets of spinal nerves including the dorsal rami (for the back) to stimulate secretion of sweat glands (sudomotor fibers)
superior cervical ganglion
post ganglionic sympathetic fibers that perform functions in the head are called these. They reach their destinations as a periarterial plexus of nerves following the branches of the carotid arteries
preganglionic sympathetic fibers
destined for the suprarenal gland travel through the thoracic splanchnic nerves and pass through the prevertebral ganglia (collateral) WITHOUT synapsing.
chromaffin cells
secretory cells of suprarenal medulla where preganglionic sympathetic fibers terminate
chromaffin cells
modified postganglionic sympathetic neurons, release epinephrine and norepinephrine into the bloodstream producing a widespread sympathetic response
preganglionic parasympathetic fibers
have their cell bodies in the brainstem or in the second through fourth sacral levels of the spinal cord
craniosacral outflow
the second through fourth sacral levels of the spinal cord
parasympathetic innervation
there is NONE of this to the limbs, and only one know innervation to the body wall
parasympathetic ganglia
only four pairs of these located in the head
ciliary ganglion
located in the orbital cavity
pterygopalatine ganglion
located in the pterygopalatine fossa
otic ganglion
located in the infratemporal fossa
submandibular ganglion
located in the floor of the mouth
myelinated preganglionic fibers
which exit the brainstem are carried away on four cranial nerves, CN 3, 7, 9 and 10.
oculomotor nerve
ciliary ganglion
facial nerve
pterygopalatine ganglion and submandibular ganglion
glossopharyngeal nerve
otic ganglion
vagus nerve
carries approximately 75% of the bodies preganglionic parasympathetic fibers
preganglionic parasympathetic fibers
these of the vagus nerve end on minute collections of parasympathetic ganglion cells (postganglionic parasympathetic neurons) distributed through the neck, thorax, and most of the abdomen.
vagus nerve
provides innervation to all of the thoracic viscera and most of the GI tract from the esophagus to the left colic flexure (foregut and midgut derivatives).
pelvic splanchnic nerves
preganglionic parasympathetic fibers originating from cell bodies in the second thru fourth sacral spinal cord segments exit the spinal cord by way of the ventral roots and ventral rami of sacral spinal nerves S2, S3, S4
pelvic splanchnic nerves
transmit their preganglionic parasympathetic fibers to minute collections of parasympathetic ganglion cells on or close to abdominal and pelvic viscera.
pelvic splanchnic nerves
begin innervating structures where the vagus nerves leave off. involved with the innervation of the descending colon, sigmoid colon, rectum, and all the other pelvic organs.
parasympathetic system
distributes ONLY to the head, visceral cavities of the trunk and erectile tissues. with the exception of the external genitalia, it does not reach the body wall or the limbs