Functionally, the nervous system has two main subdivisions: the somatic, or voluntary, component; and the autonomic, or involuntary, component. At the most basic level, the function of the nervous system is to send signals from one cell to others or from one part of the body to others. One is by releasing chemicals called hormones into the internal circulation, so that they can diffuse to distant sites. At a more integrative level, the primary function of the nervous system is to control the body. The autonomic nervous system regulates certain body processes, such as blood pressure and the rate of breathing that work without conscious effort, according to Merck Manuals. The somatic system consists of nerves that connect the brain and spinal cord with muscles and sensory receptors in the skin.