Autonomic Nervous System

Pheochromocytoma

A rare catecholamine secreting tumor of neuroectodermal chromaffin cells Causes sustained hypertension

Excitatory neurotransmitters of Smooth muscle of GIT

Acetylcholine and Substance P

Adrenal medulla distinct characteristics

Analogous to Sympathetic ganglia The pre ganglionic fibers of splanchnic nerves do not synapse in celiac ganglia and terminate here to secrete epinephrine and norepi.

Celiac ganglion pathway

Axons from IML t5 to t9 exits through ventral roots passes through white rami and goes to sympathetic chain without synapsing and forms the GREATER SPLANCHNIC NERVE. Axons from T10-T12 follow similar path and form lesser and least splanchnic nerves. They all synapse postganglionic axon in celiac ganglion. Post ganglionic fibers innervate abdominal viscera

Two layers of neurons of Enteric system

Both found in smooth muscles Myenteric(Auerbach's)-GI motility Submucosal(Meissner's)-water and ion movement across epithelium

Sypathetic trunks

Contain paravertebral ganglia where preganglionic fibers synapse

Iris and ciliary body parasympathetic innervation

EW leave brainstem through CN III. Synapse on ciliary ganglion located in orbit Postganglionic innervates smooth muscle of iris(Miosis) and circumferential muscles of the ciliary body(contraction causes relaxation of suspensory ligaments of the lens(more convex) better for near vision

Superior Salivatory nucleus

FACIAL NERVE(VI) Lower PONS Lacrimal glands, Sublingual and Submandibular salivary glands.

Inferior Salivatory nucleus

Glossopharyngeal Nerve(IX) Caudal to superior one but in upper medulla Parotid Salivary Gland

Spinal Parasympathetic Preganglionic Neurons

IML of S2-S4

Iris and ciliary body of the eye Sympathetic innervation

IML of T1 synapse on superior celiac ganglia and they synapse on iris Mydriasis-dilation of pupil

Sublingal and Submandibular Salivary Glands sympathetic innervation

IML of T1-T4 neurons synapse on superior celiac ganglion Postganglionic axons pass through external carotid arterial plexus and innervate these glands viscous saliva

Sympathetic innervation of the lungs

IML of T1-T4 synapse on T1-T4 ganglia of sympathetic chain. Post ganglions innervate smooth muscle of bronchial tree. Bronchodilation

Parotid Gland sympathetic

IML of T1-T4 synapse on superior cervical ganglion. Post ganglionic Runs through external carotid arterial plexuses viscous secretions

Urinary bladder sympathetic innervation

IML of T12-L2 synapse on inferior mesenteric ganglion Postganglionic fibers reach bladder through hypogastric plexus and synapse on blood vessels of bladder

Parotid Gland parasympathetic

Inferior Salivatory Nucleus in upper medulla exits through glossopharyngeal nerve(IX). They pass through the tympanic plexus and synapse on otic ganglia. Postganglia runs through auricular temporal nerve to parotid gland watery secretions

Stellate ganglia

Last two of cervical ganglia and first two thoracic ganglia

Edinger Westphal nucleus

Nucleus of Occulomotor Nerve III Preganglionic parasympathetic neurons. Midbrain constrictor of iris and ciliary body

Inferior mesenteric ganglion

Preganglionic Fibers form L1 and L2 travel through sympathetic trunks and travels in lumbar splanchnic nerves and synapse here. Postganglionic fibers pass through inferior hypogastric plexus synapse on transverse and descending colon and urinary bladder, male and female sex organs

Synapsing on inferior hypogastric plexus

Preganglionic fibers from L1 and L2 pass through sympathetic chains and pass through paravertebral ganglion and synapse on inferior hypogastric plexus. Postganglionic fibers synapse on bladder and male and female erectile organs

Synapsing on paravertebral ganglia

Preganglionic fibers from L1 and L2 pass through sympathetic chains and synapse here. Postganglionic fibers reenter the spinal nerve and via gray rami and innervate blood vessels, sweat glands, and erectile muscles of some hair follicles in lower limb and lower part of trunk.

Interuption of sympathetics to upper eyelid causes

Pseudoptosis enopthalmos(sinking of eyeball)

Parasympathetic innervation of the heart

Region surrounding compact zone of nucleus ambiguous Also from dorsal motor nucleus of vagus both in medulla. Exits through vagus and synapses on postganglionic neurons in heart

Superior Mesenteric ganglion

Some pre ganglionic fibers pass through celiac ganglion and synapse here. Innervates distal portions of small and large intestine(ascending and transverse colon)

sublingual and Submandibular Parasympathetic innervation

Superior Salivatory Nucleus leave lower pons through Facial nerve. They exit through chorda tympani branch and synapse on submandibular ganglia Watery saliva

Activation of salivary glands are controlled by

Sympathetic(viscous) and Parasympathetic(Watery) innervation

Sympathetic innervation of heart

T1-T4 enter via ventral roots and synapse on thoracic ganglia(1-4) and inferior, middle and superior cervical ganglia or stellate ganglia Post ganglionic innervates all regions of the heart

Kidney Sympathetic innervation

T5-T9 synapse at celiac ganglia Postganglions innervate kidney renal artery constriction

Upper eyelid ANS innervation

Tarsal smooth muscle of Superior Levator Palpebrae(T1-T4 pre gang to sympathetic postganglionic fibers of superior cervical ganglion) Orbital muscles of Mueller-holds eyeball in forward position

Nucleus Amibiguus

Ventral medulla Compact Region-Larynx and Pharynx Surround Compact Region-Decreases heart rate

Enteric Division

consists of neurons located in the wall of the gut that regulate GI motility and Secretion Intrinsically active

Parasympathetic of kidney

dorsal motor nucleus of vagus and enters kidney along renal arteries. Vasodilation of vascular bed

Parasympathetic innervation of the lungs

dorsal motor nucleus of vagus, travels to throacic cavity in vagus nerve and synapses to postganglionic neurons in lung. Postganlions innervate smooth muscle of bronchial tree Bronchoconstriction

Spinal sympathetic preganglionic and viscerotopy

eyes are most rostral GI tract most caudal

Preganglionic neurons of ANS(sympathetic are located

lateral horn of T1-L2 S2-S4

Prevertebral ganglia

located near the organ Postganglionic fibers that innervate abdominal viscera are located here

Dorsal Motor Nucleus of Vagus

lower dorsal medulla Lungs pancreas and GIT(peristalsis) Some Cardiac parasympathetic innervation

Parasympathetic ganglia are located where

near organs Short post sympathetic fibers Sympathetics have long

ANS axon characteristic pre and post ganglia

preganglionic are myelinated Post are non myelinated

Lacrimal sympathetic?Parasympathetic?

same as Sublingual and Submandibular Superior Salivatory Nucleus(lower pons) exits through greater petrosal branch of Facial nerve and synapses on pterygopalantine ganglion. Reaches lacrimal gland through lacrimal nerve Secretion of tears

White Rami

where the myelinated preganglionic axons enter the sympathetic chains Only located in thoracolumbar regions of sympathetic chain

Gray rami

where unmyelinated postganglionic axons exit the paravertebral ganglia Located along all of sympathetic chain