Human Peripheral Nervous System

Human Peripheral Nervous System - groups of motor neurons...

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Human Peripheral Nervous System The  peripheral nervous system  is a collection of nerves that connect the brain and  spinal cord to other parts of the body and the external environment. It is subdivided into  the sensory somatic system and the autonomic nervous system.  The  sensory somatic system  carries impulses from the external environment and the  senses. It consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves. The  sensory somatic system permits humans to be aware of the outside environment and  react to it voluntarily.  The  autonomic nervous system  works on an involuntary basis. It consists of two 
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Unformatted text preview: groups of motor neurons and a set of knotlike groups of cell bodies called ganglia . Motor neurons extend to and from the ganglia to the body organs. One subdivision of the autonomic nervous system is the sympathetic nervous system. Impulses propagated in this system prepare the body for an emergency. They cause the heartbeat to increase, the arteries to constrict, the pupils to dilate, and other changes to take place. The other subdivision is the parasympathetic nervous system. Impulses in this system return the body to normal after an emergency has occurred....
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This note was uploaded on 11/11/2011 for the course BIO 101 taught by Professor Pesthy during the Fall '07 term at Texas State.

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