Autonomic nervous system

AUTONOMIC NERVOUS SYSTEM

By AYOTUNDE BAMKEFA(case study)

Outline Introduction Function Clinical Correlation

Introduction The nervous system is a network of

specialized cells that helps the body react to changes in it’s external and internal environment,

Divided structurally into CNS and PNS Divided functionally into SNS and ANS

Autonomic Nervous System

is also know as the visceral nervous system or the visceral motor system.

It controls the unconscious body functions such as heart rate , digestion ,breathing patterns etc.

ANS is further divided into sympathetic and parasympathetic systems.

A Third special division of the ANS is the Enteric nervous system(at times classified under PNS)

The pathways of the first two divisions of the ANS vary by

The location of the presynaptic cell bodies

The nerves that conduct the presynaptic fibers from the CNS.

Sympathetic Division Also known as Thoracolumbar

Division Fight or flight response Presynaptic cell bodies come from

one location ;ACh Postsynaptic cell bodies are found in

two places; paravertebral and prevertebral ganglia ; noradrenaline

Parasympathetic Division Also known as Crainosacral outflow Response that returns the body to

it’s regular state Presynaptic cell bodies are located

in two locations ;ACh Postsynaptic cell bodies are found in

the head, visceral cavities of the trunk and erectile tissue of the external genitalia ;ACh, NO2

Enteric Nervous System This is a complex autonomic

ganglia found in the walls of the stomach and small intestine.

Collected into two ganglia: myenteric (Auerbach’s) and submucosal (Meissner’s ) plexuses.

Neurotransmitters : ACh, substance P, 5HT, enkephaline.

Funtion

When Changes occur in the body(visceral), either as a result of factors from the external or internal environment, the autonomic nervous system instigates compensatory measures.

Meaning it regulates the reactions of the body(smooth and modified cardiac muscles ,secretory cells).

The next slide shows how the sympathetic and parasympathetic nervous system work together .

Clinical Corelation1. Dysautonomia There is an imbalance between the

sympathetic and parasympathetic systems.

Symptoms include frequent , vague but disturbing aches and pains. Faintness, fatigue and inertia, severe anxiety attacks, tachycardia, hypotension, poor exercise tolerance, gastrointestinal symptoms, sweating, dizziness, blurred vision, numbness, tingling, anxiety and depression.

It could occur on it’s own or it could manifest in disorders like Marfan’s syndrome, Ehlers- Danlos syndrome, multiply system atrophy(shy- drager syndrome), people with joint hypermobility etc

Causes : viral illness, brain injury, genetic factors, pregnancy

Maneuvers to counter it :crossing of legs in front or behind, squatting position and tying shoes position.

2. Pure autonomic failure(Bradbury-Eggleston syndrome)

A form of Dysautonomia that occurs Mid – life or latter in life, more common in men than women

Symptoms : dizziness, fainting(caused by orthostatic hypotension) ,neck pain, visual disturbance , chest pain, fatigue, sexual dysfunction

Cause : loss of cell of the IML Column, loss of catecholamine uptake.

Drugs : vasopressors (e.g. fludrocortisone) and compression

References http://www.scholarpedia.org/article/Autonomic_n

ervous_system http://www.americanheart.org/presenter.jhtml?id

entifier=4463 http://users.rcn.com/jkimball.ma.ultranet/Biology

Pages/P/PNS.html http://users.rcn.com/jkimball.ma.ultranet/Biology

Pages/P/PNS.html http://greenfield.fortunecity.com/rattler/46/auton

omic.htm Clinical Anatomy, Keith Moore http://en.wikipedia.org/wiki/

Pure_autonomic_failure