anatomically The whole nervous system can be anatomically divided into: * Central nervous system. * Peripheral nervous system. Physiological organization 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.  2 nd, 3 rd and 4 th 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: RRelay stations. RRelease of chemical transmittion DDistributing function.  Regeneration of post ganglionoic fibers.

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 emergency situation.

Horner's Syndrome: damage of the superior cervical sympathetic ganglion leads to:  Ptosis.  Miosis.  Anhydrosis.  Vasodilatation.

Origin and distributio n of parasympat hetic 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.