Dr Md.Hosne Mobarak
Resident (Phase –A)
Physical Medicine and Rehabilitation,
BSMMU, Dhaka

 Two important plexuses of nerve cells and fibers extend continuously along and around length of gastrointestinal tract from esophagus to anal canal

Submucous or Meissner plexus lies between mucous membrane & circular muscle layer
 Myenteric or Auerbach plexus lies between circular & longitudinal muscle layer

 Meissner plexus controls sectration of glands of the mucous membrane

Auerbach plexus controls movements of the gut wall
 It has been suggested that while the enteric plexuses can
coordinate the activities of the gut wall, the parasympathetic and sympathetic inputs modulate these activities

Enteric Nervous System


Preganglionic parasympathetic fibers enter the abdomen in anterior (left) and posterior (right) vagal trunks

Terminates on postganglionic neurons in the myenteric
(Aurbach) & submucosal (Meissner) plexuses
 The parasympathetic nerves stimulate peristalsis & sectretion of mucus membrane and relax the sphincters

 Preganglionic sympathetic nerve fibers pass through the thoracic part (T5-11) of the sympathetic trunk and enter the greater and lesser splanchnic nerves

Synapes with postganglionic neurons in the celiac & superior mesenteric ganglia
 The sympathetic nerves inhibit peristalsis & sectretion of mucus membrane and contract the sphincters;


Preganglionic parasympathetic fibers originate in the gray matter of the spinal cord from the 2 nd to the 4 th sacral segments forming
Pelvic Splanchnic Nerve
 Synapes with postganglionic neurons in the myenteric (Aurbach) & submucosal (Meissner) plexuses

The postganglionic fibers supply the smooth muscle & glands which
stimulate peristalsis and secretion.

 Preganglionic sympathetic nerve fibers pass via lumbar
(L1-2) part of the sympathetic trunk
 Synapes with postganglionic neurons in the inferior mesenteric ganglia

The sympathetic nerves inhibit peristalsis & secretion

Autonomic Innervation of Gastrointestinal Tract

 The gallbladder & biliary ducts receive postganglionic parasympathetic & sympathetic fibers from the hepatic plexus

Parasympathetic fibers derived from the vagus are thought to be motor fibers to the smooth muscle of the gallbladder & bile ducts and inhibitory to the sphincter of Oddi

Sympathetic fibers relaxes the Gallbladder

 Esophagial dysmotility

Gastroparesis Diabeticorum

Diarrhoea
 Constipation

Fecal Incontinence

 A congenital condition in which there is a failure of development of the myenteric (Aurbach) plexus in the distal part of the colon

The involved part of the colon posses no parasympathetic ganglion cells and peristalsis is absent

This effectively blocks the passage of feces, and the proximal part of the colon becomes enormously distended

 Following Spinal Cord Injury
1) Parasympathetic influence on the peristalsis activity of the descending colon, sigmoid colon and the rectum is lost
2) Control over the abdominal musculature and sphincter of the anal canal may be severely impaired

Pressure in the lumen rises – response by contracting

Local reflex acts if the sacral segments of the spinal cord and cauda equine are intact

Low force of contraction in rectal wall – constipation & impaction

 Sympathetic fibers pass through the lower thoracic part of the sympathetic trunk & the lowest thoracic splanchnic nerve to join the renal plexus around the renal artery

The sympathetic nerves are vasoconstrictor in action to the renal arteries within the kidney
 Parasympathetic fibers enter the renal plexus from the vagus.
 The parasympathetic nerves are thought to be vasodilator in action

 Sympathetic fibers descend to the gland in the greater splanchnic nerve, a branch of the thoracic part of the sympathetic trunk

The sympathetic nerves stimulate the increase the output of epinephrine and norepinephrine
 There is no parasympathetic innervation of the medulla of the suprarenal gland

Autonomic Innervation of Kidney and Suprarenal gland

 The internal anal sphincter is innervated by postganglionic sympathetic fibers from the hypogastric plexuses
 The sympathetic nerves cause internal anal sphincter to contract

 The sympathetic fibers originate in the first and second lumbar ganglia of the sympathetic trunk and travel to the hypogastric plexuses
 The parasympathetic fibers arise as the pelvic splanchnic nerves from the second, third, and fourth sacral segments of spinal cord


The sympathetic nerves to the detrusor muscle have little or
no action on the smooth muscle of the bladder wall and are distributed mainly to the blood vessels
 Sympathetic nerves to the sphincter vesicae play only a minor
role in causing contraction of the sphincter in maintaining urinary continence

The parasympathetic nerves stimulate the contraction of the smooth muscle of the bladder wall and, in some way, inhibit the contraction of the sphincter vesicae

Autonomic Innervation of the Internal Sphincter of Anal Canal & Urinary Bladder

 The initial vascular engorgement is controlled by the parasympathetic part of the autonomic nervous system
 The parasympathetic fibers originate in the gray matter of the
2 nd , 3 rd and 4th sacral segments of the spinal cord

The parasympathetic nerves cause vasodilatation of the arteries & greatly increase the blood flow to the erectile tissue

 Sympathetic fibres originates from L1-2 segment of spinal cord
 The postganglionic fibers are then distributed to vas deferens, the seminal vesicles, and the prostate through the hypogastric plexuses.

The sympathetic nerves stimulate the contractions of the smooth muscle in the walls of these structures & cause the spermatozoa, together with the secretions of the seminal vesicles & prostate, to be into urethra

Autonomic Innervations of the Male Reproductive Organs

 Preganglionic sympathetic nerve fibers leave the spinal cord at segmental levels T12 and L1 supply the smooth muscle of the uterus

Parasympathetic preganglionic fibers leave the spinal cord at levels S2–4

Although it is recognized that the uterine muscle is largely under hormonal control, sympathetic innervation may cause uterine contraction and vasoconstriction
 whereas parasympathetic fibers have the opposite effect

 Afferent pain fibers from fundus and the body of uterus ascend to spinal cord through the hypogastric plexuses, entering it through posterior roots of 10th,11th,
&12th thoracic spinal nerves
 Fibers from the cervix run in the pelvic splanchnic nerves and enter the spinal cord through the posterior roots of the 2nd, 3rd & 4th sacral nerves

Autonomic Innervation of Uterus

 Bladder dysfunction

Erectile dysfunction

Retrograde ejaculation
 Dyspareunia

 It’s a dysfunction of the urinary bladder due to disease of the central nervous system or peripheral nerves involved in the control of micturition.
 Neurogenic bladder usually causes difficulty or full inability to pass urine without use of a catheter or other method.

Type
Atonic (lower motor neuron)
Site of lesion
Lesions of sacral segments of cord
(conus medullaris)
Lesions of sacral roots and nerves
Loss of detrusor contraction
Hypertonic (upper motor neuron)
Pyramidal tract lesion in spinal cord or brainstem
Result
Difficulty initiating micturition
Bladder distension with overflow
Cortical Post-central
Pre-central
Frontal
Urgency with urge incontinence
Bladder sphincter Incoordination
(dyssynergia)
Incomplete bladder emptying
Loss of awareness of bladder fullnes
Difficulty initiating micturition
Inappropriate micturition
Loss of social control