Autonomics Flashcards
what do autonomic plexuses contain?
Preganglionic parasympathetic fibers
Preganglionic sympathetic fibers
Postganglionic sympathetic fibers
Prevertebral sympathetic ganglia
what are the two sources of sympathetic innervation to the pelvis?
Lumbar splanchnic n.
Sacral splanchnic n.
(both preganglionic sympathetic)
what is the one source of PS innervation to the pelvis?
Pelvic splanchnic nn (preganglionic PS)
what do efferent sympathetics do?
vasoconstriction, contraction of sphincter muscle, inhibition of peristalsis, inhibition of glandular secretions
What does PS in pelvis do?
vasodilation, peristalsis, contraction of detrusor muscle of bladder and myometrial muscle of uterus
what does superior hypogastric plexus supply?
branche sto ureter and genital organs (epididymis, tesis, ovary)
what does inferior hypogastric supply?
- supplies pelvis
- supplies prostatic plexus, rectum, ureteral plexus, urterer, penis, prostate, ovary, bladder, vagina — pretty much everything in the pelvis
- it is a continuation of the superior hypogastric plexus via the hypogastric nn.
- located along the lateral surface of the rectum
- contains PS and symp fibers
pelvic splanchnic nn.
supply PS innervation and cell bodies are located in the IMLCC at S2-4
- pelvic splanchnic nn. distribute with the inferior hypogastric and subsidiary plexuses to the pelvic and perineal organs
- postbanglionic fibers are found in the wall of the organs
()/never come from sympathetic chains!!!)
ganglion impair
where the right and left sympathetic trunks merge
Lumbar splanchnic nn.
- preganglionic neurons located in IMLCC at T11-L2
- they enter sympathetic chain, do not synapse, and exit as lumbar splanchnics
- lumbar splanchnic nn. enter the intermesenteric and superior hypogastric plexuses and synapse with postganglionic neurons found there
- postganglionic neurons travel from the superior hypogastric plexus to the inferior hypogastric plexus via the hypogastric nn. - where they then spread to pelvis.
- ** this is the major route of symp innervation to the pelvis***
hypogastric nn.
postganglionic sympathetic fibers. connect eh syperior hypogastric plexus with the inferior hypogastric plexus
subsidiary plexuses
postganglionic fibers spread to pelvic viscera from inferior hypogastric lexuses via subsidiary plexus or fvia inferior hypogastric plexus itself
Sacral splanchnics
- ** minor route of symp. innervation to splanchnics***
- preganglionic cell bodies located in IMLCC at T12-L2
- these fibers descned within the symp. chain to sacral levels and exit without synapsing as sacral splanchnic nn.
- they enter the inferior hypogastric plexus where they synapse
- postganglionic fibers then spread to pelvic visceria via subsidiary plexus and inferior hypogastric plexus
What is perineal innervation?
PS: via cavernous plexus (continuation of uterovaginal/prostatic plexuses. cavernous nn. distribute with branches of pudendal nn.)
Symp: via pudendal n (S2,3,4)
provides autonomic innervation to erectile tissues, urethral mucosa and glands
Urinary bladder innervation
via inferior hypogastric plexus
Symp: T10-L2 via lumbar and sacral splanchnic nn. (results in contraction of trigonal muscle and smooth muscle portion of sphincter urethrae mechanism; vasomotor)
PS: S2-4 via pelvic splanchnic nn. (contraction of detrusor mm. and urination)
Urethra innervation
via inferior hypogastric plexus –> prostatic or vesicle plexus
Symp: via lumbar/sacral splanchnics (L1-L3)
PS via pelvic splanchnics (S2-4)
innervation of perineal urethrae provided via pudendal nn (S2-4)
Testes innervation/ male repro innervation
distributes via testicular plexus
Symp: from T10-11 via lumbar and sacral splanchnics - controls emission (contraction of smooth m. of ductus deferens, seminal glands, ejac duct, prostate –> delivery of semen to urethra)
** also carry pain fibers **
ejaculation also controlled somatically via pudendal nn. from forceful contraction of bulbospongiosus m.
PS: S2-4 via pelvic splanchnic nn.
What supplies penis/glands of perineum
dorsal n. of penis: supplies sensory and sympthatic innervation
cavernous nn. supply PS : causes erection via cavernous nn. increasing PS tone to erectile tissue helicine aa, causing filling and engorgement of erectile bodies. contraction of the bulbospongiosus and ischiovacernosus mm. is also involved, and prevents venous drainage of blood.
remission is a sympathetic response involving contraction of helicine aa.
how does autonomic innervation control urination?
As the bladder fills, an increasing number of stretch receptors begin to fire. These stretch neurons travel to the spinal cord with the pelvic splanchnic nerves (S2,S3,S4). Ascending fibers then travel through the spinal cord to the brainstem micturition center.
Descending fibers from the brainstem then activate the motor (GVE-P) component of the pelvic splanchnic nerves.
The pelvic splanchnic nn cause contraction of detrusor mm and emptying of the bladder.
Descending fibers also cause relaxation of the sphincter urethrae muscles (inhibiting both the sympathetically-innervated internal portion…..
and somatically innervated external portion)
what innervates the ovaries and uterine tube?
ovarian plexus
Symp: innervation from T10-11 via lesser splanchnic nn.
** also carrier pain fibers
PS: innervation from vagus n?
what innervates the uterus, cervix and superior portion of vagina?
Inferior hypogastric plexus –> uterovaginal plexus
Symp: T12-L2 via lumbar and sacral splanchnic nn.
* pain from uterus
PS: S2-4 bia pelvic splanchnic nn - results in contraction of smooth muscle
** pain from cervix and upper vagina
where does pudendal n. innervate in women/
innervates inferior 1/4 of vagina via somatic innervation
what innervates the rectum/anal canal superior to pectinate line?
- inferior hypogastric plexus –> rectal plexus
Syp: L1-2 via lumbar/sacral splanchnics (inhibits gland secretion)
* motor control of internal sphincter m.
PS: S2-4 via PS nerves (contraction of smooth m. –> peristalsis; stimulates glandular secretion)
** pain from rectum sensed **
what innervates the anal canal?
superior to pectinate line –> inferior hypogastric plexus
inferior to pectinate line –> somatic innervation from pudendal n.
