Back to The Human Body & Its Miracle Make-Up A Quick Tour of Appreciation

The main role of the muscular system is to provide movement. Muscles work in pairs – for example the biceps and the triceps - to move limbs and provide the organism with mobility. Muscles also control the movement of materials through some organs, such as the stomach and intestine, the heart and circulatory system. On average, the skeletal muscles make up more than 40% of the weight in a man’s body. The ratio of muscle tissue to fat tissue in a woman is lower than that in a man. There are three types of muscle tissue: Skeletal muscles which are striped (striated). These are under your own voluntary control. There are continuous messages being sent to and from the brain. The more you use certain muscle groups, the more efficient they become in performing those tasks. Cardiac muscle has a less striped appearance. Smooth muscles have no striping. Both the cardiac and smooth muscles are not under your voluntary control. Your control over their reactions is limited. In the digestive tract, there are muscles in the walls of the esophagus, stomach and intestines. In the respiratory system, smooth muscles are arranged in a circular pattern to help control the width of the passages. Your circulatory system is regulated by smooth muscle in the walls of your blood vessels. The cardiac muscle cells of the heart keep the blood flowing through the circulatory system throughout life. The smooth muscles in the urinary system keep urine flowing from the kidneys to the bladder. Exercise will increase the size of individual muscle cells, but will not increase the number of cells.

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