MUSCLES Like a machine, your body consists of

many parts that move. Those parts are your bones and muscles.

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.

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?)

Parts of the Muscle System 3 Types of Muscle

Smooth, Skeletal, Cardiac Tendons – Attach muscle to bone

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.

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.

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.

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