(3) Enteric Nervous System

Enteric nervous system

brain of the gut; coordinates digestion independently of CNS, but communicates with both sympathetic and parasympathetic divisions

Myenteric/Auerbach’s plexus

controls GI motility

Submucosal/Meissner’s plexus

regulates secretion, absorption, and blood flow

Enteric system neurotransmitters

• Ach

• nitric oxide

• serotonin

• dopamine, ATP

Parasympathetic effect on enteric nervous system

enhances activity, rest and digest

Sympathetic effect on enteric nervous system

inhibits activity, fight or flight

Amyloidosis

inherited ANS disorder, amyloid buildup damages autonomic nerves and organs

Fabry disease

fat accumulation in vessels → kidney, heart, and nerve dysfunction

Hereditary sensory autonomic neuropathy/Charcot-marie-tooth

weakness, sensory loss, peripheral neuropathy

Porphyria

metabolic defect; acute type affects nervous system, cutaneous type affects skin

ANS cardiovascular injury

• low resting BP

• postural hypotension

• sudden hypertension

• bradycardia/arrhythmia

Thermoregulatory ANS injury

• body temp matches environment

• quad fever

• sweating disorders

GI ANS injury

• increased gastric acid secretion

• gallbladder stasis

• slow distal colon transit

• reflex colorectal contractions

Bipolar neurons

rare, found in retina, olfactory epithelium, vestibulocochlear ganglia

Unipolar neurons

sensory neurons; cell bodies in spinal/cranial ganglia

Multipolar neurons

most common; found in CNS and autonomic ganglia