Wikijunior:Human Body/Muscles

Muscles are the organs that make us move. All our movements from running, jumping, to blinking and smiling are made by our muscles. Muscles are everywhere. They can be tiny as in the ear or huge like leg muscles. Although no muscle is directly visible you can watch many of them in action in the mirror, when you flex your muscles.

What does a muscle look like?
A muscle is usually a long round organ. The color is red. A muscle is flexible and shortens and thickens during a contraction. The figure on the right shows a series of magnifications of a muscle. You can see that a muscle is a collection of fibres or strings, each of which is capable of contraction. The added force of these fibers is the strength of the muscle.

What are the parts of a muscle?
A muscle has two ends each of which attach to some other organ, usually a bone. These connectors are called tendons.

What is the function of a muscle?
Without muscles, we can not survive. Muscles produce almost all movements in our body. We need healthy muscles to be able to walk, move, and even smile. The human body has about 620 muscles that it uses for its movement. In addition there are many more that work automatically. The muscles in our heart move blood around the body, the chest muscles help us breathe and the stomach muscles help us digest food.

How does a muscle interact with other parts of the body?
Muscles connect with all of the other parts of the body. Muscles in the heart pump blood throughout the body. The diaphragm is a large muscle that allows us to breathe. Muscles from our mouth to our stomach and beyond help us swallow food and move it through the digestive system. Even our eyes have muscles that let us look around and see our surroundings. The muscles do movement by becoming shorter and pulling the bones to which they are attached.

How can you keep your muscles healthy?
Our muscles are kept healthy through regular exercise. Eating properly and especially including a quality protein source in your diet will help keep your muscles healthy.