The muscular system is made up of tissues that work with the skeletal system to control movement of the body. Other muscles, like the ones in your stomach, heart, intestines and other organs, are involuntary. Each of these has the ability to contract and expand, which allows the body to move and function. Skeletal muscles help the body move. Smooth muscles , which are involuntary, are located inside organs, such as the stomach and intestines.
Cardiac muscle is found only in the heart.
The nervous system is made up of the brain, the spinal cord, and nerves. One of the most important systems in your body, the nervous system is your body's control system. It sends, receives, and processes nerve impulses throughout the body. These nerve impulses tell your muscles and organs what to do and how to respond to the environment. The central nervous system consists of the brain and spinal cord.