Sun September 30, 2012 By:

what is a significance of PNS? name the components of the nervous system & distingush between the origin of the two?

Expert Reply
Mon October 01, 2012

 The main function of the PNS is to connect the central nervous system to the limbs and organs. 

The nervous system can be divided into two parts: the central nervous system and the peripheral nervous system.

Central nervous system is the portion of the nervous system consisting of the brain and spinal cord.

The peripheral nervous system (PNS) is the system of nerves outside of the central nervous system. It is divided into:

?  Sensory Nervous System - sends information to the CNS from internal organs or from external stimuli.

?  Motor Nervous System - carries information from the CNS to organs, muscles, and glands. This system is further divided into somatic and autonomic nervous system.

  • Somatic Nervous System - controls skeletal muscle as well as external sensory organs.
  • Autonomic Nervous System - controls involuntary muscles, such as smooth and cardiac muscle. The autonomic nervous system can further be divided into the parasympathetic and sympathetic divisions.
    • Sympathetic - controls activities that increase energy expenditures.
    • Parasympathetic - controls activities that conserve energy expenditures.


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