Basic Psychology, Biology of Psychology

Nervous System

The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body.

The nervous system includes both the Central nervous system and Peripheral nervous system. The Central nervous system is made up of the brain and spinal cord and The Peripheral nervous system is made up of the Somatic and the Autonomic nervous systems.Together, these organs are responsible for the control of the body and communication among its parts.


Nervous system is the chief controlling and coordinating system of the body. It controls and regulates all activities of the body, whether voluntary or involuntary, and adjusts the individual (organism) to the given surroundings. This is based on the special properties of sensitivity, conductivity and responsiveness of the nervous system.

human_nervous_system.jpgThe protoplasmic extensions of the nerve cells form the neural pathways called nerves. The nerves resemble the electricity wires. Like the electric current flowing through the wires, the impulses (sensory and motor) are conducted through the nerves.The sensory impulses are transmitted by the sensory (afferent) nerves from the periphery (skin, mucous membranes, muscles, tendons, joints, and special sense organs) to the central nervous system (CNS). The motor impulses are transmitted by the motor (efferent) nerves from the central nervous system to the periphery (muscles and glands).
Thus the CNS is kept continuously informed about the surroundings (environment) through various sensory impulses, both general and special. The CNS in turn brings about necessary adjustment of the body by issuing appropriate orders which arc passed on as motor impulses to the muscles, vessels, viscera and glands. The adjustment of the organism to the given surroundings is the most important function of the nervous system, without which it will not be possible for the organism to survive.


Functions of nervous system

Sensory Input

  • Receptors within and near body surface
  • Send nerve impulses to CNS


  • CNS receives, processes, and interprets sensory input
    Decides what to do with it.

Motor Output

  • CNS sends out nerve impulses to effector organs (muscles and glands) in response to sensory input.




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