images.jpeg290px-Nervous_system_diagram.pngThe nervous system consists of a hundred billion nerve cells - or neurons. The nervous system basically consists of two main parts - the central nervous system (CNS) and the peripheral (PNS). The brain and the spinal chord are the main parts of the Central Nervous System and the cranial and spinal nerves make the peripheral. The peripheral system connects the sensory nerves for things such as vision, hearing, smell, and touch and other effector organs such as muscles and glands.

Another way at dividing the Nervous system is into the Somatic and Autonomic nervous system.
The autonomic nervous system is in connection with glands and internal organs like the heart, lungs, stomach, intestines, liver, kidneys and adrenal glands, bladder and reproductive organs, to mention a few. These functions stand above our will end awareness, and is instead taken care of automatically by the nervous system itself.
On the other hand, the somatic nervous system handles the muscles in our extremities, and joints and the outer skin, in other words functions that to a large extent is governed by our own will.
Another difference between the autonomic and the somatic nervous system is that while the central cell bodies of somatic neurons extend all the way out to the peripheral target organs, the autonomic neurons have to be reconnected in so called ganglia on the way to the effector organ.

The Nervous system corresponds with the brain and controls many functions that humans use everyday, such as smell and touch. It also controls emotions and other feelings that people expierence. The Nervous system also helps maintain homeostasis and works with other parts of the human body. If something goes wrong with the nervous system then homeostasis will not be kept constant.