The neurons are the basic blocks of nervous system.The neurons can be classified in to unipolar , bipolar and multipolar. it is used to detect and receive innumerable information from the sensors in our human body and thus determining the mode of response human body.The basic function of nervous system are receiving stimulus input from external and internal parts of the body directly to the brain. These inputs are processed by the cerebrum of the brain and thus response to the stimuli.In nervous system the electrical systems are in the form of nerve impulses which are used in the concept of fast responses.The human nervous systerm consist of three main divisions.That is the central nervous system , peripheral nervous system and the autonomous nervous system.The central nervous system consist of the brain and spinal cord.The peripheral nervous system consist of cranial nerves and spinal nerves.The sympathetic and parasympathetic nervous system comes under the autonomous nervous system.The central nervous system  is the site of information processing.The peripheral nervous system controls the voluntary activities of the body.The autonomous nervous system controls the involuntary activities of our body.The central nervous system are covered by three membranes together known as meninges.The inner membrane  is a known as pia matter, the middle membrane is arachnoid matter and the outer membrane is dura matter.