an animal 's brain controls that animal & the brain can control animal body through the nervous system ->  the nervous system is used for controlling the body  the muscular system is a kind of body system & a body system is a part of the body ->  the muscular system is a part of the body  the muscular system is a part of the body & the muscular system contains muscles ->  muscles are a part of the body  the nervous system is used for controlling the body & muscles are a part of the body ->  the nervous system is used for controlling the muscles  the nervous system is used for controlling the muscles & to control something can mean to coordinate something -> the nervous system is used for coordinating the muscles