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The Autonomic Nervous System. The whole nervous system can be anatomically divided into: * Central nervous system. * Peripheral nervous system. Physiological organization of the nervous system are:
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The Autonomic Nervous System The whole nervous system can be anatomicallydivided into: * Central nervous system. * Peripheral nervous system. Physiological organization of the nervous system are: * Somatic nervous system mainly deals with the voluntary and conscious aspects of neurological control. * The autonomic nervous system (ANS): deals with involuntary control mechanisms.
Divisions of the autonomic nervous system * SYMPATHETIC:thoracolumbar outflow, catabolic in function * PARASYMPATHETIC:craniosacral outflow, anabolic in function • Cranial nerves, i.e. Cr III, VII, IX & X. • 2nd, 3rd and 4th sacral segments
Autonomic ganglia Definition: A ganglion is a collection of nerve cells out side the CNS. Types: Three types: • Lateral: site for relay of sympathetic nerves. • Collateral: It is site for relay of both sympathetic and parasympathetic nerves. • Terminal:site of relay for parasympathetic nerves.
Function of autonomic ganglia: • Relay stations. • Release of chemical transmittion • Distributing function. • Regeneration of post ganglionoic fibers.
THE SYMPATHETIC NERVOUS SYSTEM Origin and distribution of sympathetic nervous system
General functions of the sympathetic nervous system: (The alarm response or stress response) In emergency conditions: e.g. in cases of fight, flight, muscular exercise, emotions, pain and cold, generalized sympathetic excitement occurs (the alarm response or stress response): • Acceleration of the heart. • Dilatation of bronchi. • Vasoconstriction in inactive regions.
Sweat secretion. • Delay muscle fatigue. • Contraction of spleen. • Glycogenolysis. • Adrenal secretion. All the above reactions prepare the body for fight or flight or to face an emergencysituation.
Horner's Syndrome: damage of the superior cervical sympathetic ganglion leads to: • Ptosis. • Miosis. • Anhydrosis. • Vasodilatation.
The Parasympathetic Nervous System Origin and distribution of parasympathetic nervous system
General functions of parasympathetic system: • Parasympathetic functions are anabolic and energy preserving • Its function becomes most apparent in a person at rest after a meal and reading a newspaper.