Illustration of the muscles of the human body (front view) in a standing adult male. There are more than 600 muscles in the human body, the most prominent being skeletal (voluntary) muscles which make up 40 to 45% of body weight.
The muscular system is a system of tissues called muscles throughout the body. It permits movement of the body. The muscular system consists of three different types of muscle tissues: skeletal, cardiac, and smooth muscles which maintains posture and provide strength, balance, movement and heat for the body to keep warm.
The muscular system in vertebrates is controlled through the nervous system. The human body contains more than 650 individual muscles served by nerves which, link each individual muscle to the brain and spinal cord. There are two types of muscles in the system and they are the involuntary muscles, and the voluntary muscles.
The muscles which are controlled by ourselves are called the voluntary muscles and the ones we can't are the involuntary muscles. The heart, or the cardiac muscle, is an example of involuntary muscle.
In the adjacent figure, muscles seen here (red) are voluntary muscles in that they are under conscious control. They are composed of bundles of specialized cells capable of contraction & relaxation to create movement. They are attached to the human skeleton by tendons (white). In this way the limbs, spine, pelvis, shoulders and head can move in relation to each other. Muscles are under the nervous control of the brain and spinal cord.