Case Study: Autonomics

Where does the sympathetic NS originate?

thoracolumbar (T1 to L2 spinal segments)

where are preganglionic sympathetic cell bodies?

lateral horn of spinal cord

where does the PS NS originate?

craniosacral (at or near the target organs)

what does the sacral portion of the PS NS give rise to?

Pelvic nerves, then pelvic plexus, then pelvic organs

First step in SS innervation reaching the head:

preganglionic fibers leave spinal cord at T1-T3

second step in SS innervation reaching the head:

enter the sympathetic chain (via white ramus communications)

third step in SS innervation reaching the head:

ascend SS chain to cranial cervical ganglion where they synapse

fifth step in SS innervation reaching the head:

postganglionic fibers follow internal carotid artery

what are the most cranial locations that the SS can synapse with other SS neurons?

cranial cervical ganglion

what are the most caudal locations that the SS can synapse with other SS neurons?

caudal mesenteric ganglion

do viscera have sensory cell bodies?

yes in the DRG

how does the SS innervation affect the eye in dogs?

cranial cervical ganglion; dilator pupil m, smooth m of periorbita, muller’s m of upper eyelid

what happens when there is loss of SS supply to the eye?

horner’s syndrome

how does the PS innervation affect the eye in dogs?

oculomotor; sphincter papillae, ciliary m

What ganglia are SS?

cranial cervical, middle cervical, cervicothoracic, sympathetic chain, celicomesenteric, adrenal, caudal mesenteric

what ganglia are PS?

ciliary, optic, pterygopalatine, mandibular, sublingual, cardiac, myenteric, submucosal, pelvic

where would you find SS POST ganglionic fibers?

gray rami communicants, internal carotid nerve, deep petrosal nerve, nerves from pre vertebral ganglia to abdominal organs

where would you find PS POST ganglionic fibers?

short ciliary nerves and from pterygopalatine, mandibular, and otic ganglion

what carries preganglionic fibers in SS NS?

ventral roots (T1-T4), white rami, sympathetic trunk, splanchnic nerves (minor, major, lumbar)

what carries postganglionic fibers in SS NS?

gray rami, nerves from CCG, deep petrosal nerve, plexus on arteries (carotid, vertebral, celiac, mesenteric)

what carries preganglionic fibers in PS NS?

CN 3, 7, 9, 10 and pelvic nerve (S1-S3)

what carries postganglionic fibers in PS NS?

short ciliary nerves, branch’s from mandibular and pterygopalatine ganglion, and auriculotemporal nerve from otic ganglion