The muscular system is the set of all the muscles that make up the human body. It is an extensive system of muscles and nervous tissue, which is distributed all through the body. In total, the human body consists of approximately 650 muscles (Shier, Butler, Lewis, 2009). The muscular system is divided into three types of muscle: cardiac muscle, smooth muscle, and skeletal muscle (p.212).
Cardiac muscle is a type of involuntary muscle found only in the walls of the heart, specifically the myocardium. Cardiac muscles contract automatically to tighten the walls of the heart in a rhythmic fashion (pp.212-216). The heart beats nonstop about 100,000 times each day (p.18). Smooth muscle is a type of involuntary muscle found within the walls of blood vessels such as in small arteries and veins. Smooth muscle is also found in the urinary bladder, uterus, male and female reproductive tracts, gastrointestinal tract, and the respiratory tract. Skeletal muscles are voluntarily controlled and are attached to bones by tendons. Skeletal muscles also vary considerably in size and shape. They range from extremely tiny strands such as in the muscle of the middle ear as large like in the muscles of the thigh (Martini, 2000). The three individual muscle types also serve five main functions. The five basic functions are movement, organ protection, pumping blood, aiding digestion, and ensuring blood flow.
The first basic function of the muscular system is movement, which is carried out by the skeletal muscles. The primary function of the skeletal muscle is to produce voluntary gross and fine motor movement. This set of voluntary muscles provides the forces that enable the body to move. A skeletal muscle links two bones across its connecting joint. When these muscles contract or shorten, the bone moves. Examples of gross motor movements are running, lifting weights, or playing sports. An example of fine motor movements or smaller movements would be blinking, talking or chewing. The skeletal muscles will also contract as a reflex to stimuli, like when the hand moves away from a hot cup of coffee (pp. 167-172).
Another basic function is to protect internal organs, which is also executed by the skeletal muscles. The abdominal cavity is not protected by bones like the heart and lungs are protected by the rib cage. Therefore, the abdominal muscles and muscles in the lower back help protect the vital organs. For example the rectus abdominus or “six pack” muscle protect the body from the front.
The third function of the muscular system is pumping blood. The cardiac muscles in our body control the pumping of blood throughout arteries and veins. The contraction of the heart muscle is involuntary and is controlled by the hearts own electrical system. The right side of the heart receives blood from the body and pumps it to the lungs. The left side of the heart receives blood from the lungs and pumps it out to the body (Shier,...