What is
The Nervous System?

The nervous system is responsible for sending, receiving, and processing nerve impulses. All the organs and muscles need the nerve impulses to function. It could be considered as the master control unit inside your body.
Sense organs provide the nervous system with information about the environment by means of senses like sight, hearing, smell, taste, and touch.
Nerves are connected throughout the whole body to the brain. They carry the information throughout the body in the form of electrochemical signals called impulses. These impulses travel from the brain and spinal cord to the nerves located throughout the body.

What are
Neurons?

The nervous system is largely made up of specialized cells called neurons. Each of this neuron has a cell body, or cyton, which contains the nucleus and organelles. It takes the corporation of three systems to carry out the mission of the nervous system. They are the central and peripheral nervous systems.
The central nervous system has the responsibility for issuing nerve impulses and analyzing sensory data, and includes the brain and spinal cord.
The peripheral nervous system is responsible for carrying these nerve impulses to and from the body. Many structures, includes the many craniospinal nerves which branch off the brain and the spinal cord.

What is the
Physiological Division?

A less anatomical but much more functional division of the human nervous system is that classifying it according to the role that the different neural pathways play - somatic and autonomic nervous systems.
The somatic nervous system processes sensory information and controls all voluntary muscular systems within the body, with the exception of reflex arcs.
The autonomic nervous system is composed of the sympathetic and parasympathetic systems and is responsible for regulating and coordinating the functions of vital structures in the body.