Autonomic Nervous System

¢The portion of the nervous system that controls the visceral function of the body is called ANS i.e. arterial pressure ,GI motality , secretion , UB emptying ,sweating , body temp etc .

¢Can change the visceral functions with in 3 to 5 seconds.

¢Mainly activated by centers located in spinal cord , brain stem , hypothalamus , portion of cerebral cortex.

¢Afferent signal .

¢Efferent signal are transmitted to the body through sympathetic  and para sympathetic systems.

¢To paravertabral sympathetic chains of ganglia on two sides of vertabral column.

¢To prevertabral ganglia (coelic and hypogastric ) it orignate in spinal cord between segments  T1- L2.

¢Composed of two portions i.e. pre ganglion and post -ganglion  neuron.

¢Pre ganglion neuron lies in inter-medio lateral horn of spinal cord.

¢Post ganglion fibers originate from sympathetic chain of ganglion and then enter to the organ.

—Fibers leaves CNS through crainal nerves – III ,VII, IX, X and S2 & S3.

—75% fibers pass through vagus nerve. i .e. it supply heart ,lungs ,esophagus, stomach , small intestine ,proxmial half of colon , liver , gall bladder , pancras, upper portion of ureter.

—All preganglionic neurons are cholinergic.

—Postganglionic fibers of para sympathetic  are cholinergic  and sympathetic are adrenergic except sweat glands , piloerector muscles and few blood vessels.

¢X Cranial Nerve: heart ,lungs ,esophagus , stomach , entire small intestine , proximal half of colon , liver , gall bladder , pancreas ,upper portion of ureter .

¢III Nerve :pupillary sphincters , ciliary muscles of eye .

¢VII Nerve : lacrimal , nasal , sub mandibular secretions.

¢IX Nerve : parotid gland .

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