MUSCLES

1. MUSCLES • Like a machine, your body consists of many parts that move. Those parts are your bones and muscles.

2. Muscle Action • There are two types of muscle actions • Voluntary – You control the movement • Involuntary – You can’t control the movement • When you pick up an object it is a voluntary movement. • However, the beating of your heart and movement of your digestive track are involuntary.

3. Muscle System Function • The major function of the muscular system is to move bones. It also provides support and protection for your organs. • Muscles and bones work together with your nervous system to move your body. (what three systems are these again?)

4. Parts of the Muscle System • 3 Types of Muscle • Smooth, Skeletal, Cardiac • Tendons – Attach muscle to bone

5. Skeletal muscles • Skeletal muscles are made of skeletal muscle tissue. Most of your body is skeletal muscle. • Skeletal muscle is made up of fibers bound together by connective tissue which also contain blood vessels and nerves. • Muscle fibers contain long muscle cells with thousands of mitochondria for energy.

6. Flexors and Extensors • Muscles work in pairs called flexors and extensors • To bend a part of your body, a flexor is used. • To straighten part of your body, an extensor is used. • They provide ALL movement of your skeleton.

7. Skeletal Muscles • All muscle works in pairs and to cause movement muscles must contract or extend. • When a muscle contracts, it causes muscle fibers to shorten (contract). • When a muscle relaxes, it causes muscle fibers to extend and return to their original length.

8. Healthy Muscles • Skeletal muscles tire quickly. To keep them healthy (as well as your entire body healthy) you should do resistance exercises (weights). This increases muscle strength. • Aerobic exercise also increases the endurance of skeletal muscle