The Muscular System Helps Your Body Move

1. The Muscular System Helps Your Body Move Most muscles work together in pairs. One muscle pulls while the other muscle relaxes. When you bend your arm the biceps muscle pulls and the triceps muscle relaxes. When you make your arm straight, the biceps muscle relaxes and the triceps muscle pulls.

2. The Function of Muscles Muscles are very important. They help you do almost everything — from pumping blood throughout your body to lifting your heavy backpack. You control some of your muscles and others, like your heart, do their jobs without you thinking about them at all.

3. Did you know? • You use 17 muscles when you smile. • You use 43 muscles when you frown.

4. Muscle System Functions • Provides voluntary movement of body • Enables breathing, blinking, and smiling • Allows you to hop, skip, jump, or do push-ups • Maintains posture • Produces heat

5. Functions Continued • Causes heart beat • Directs circulation of blood • Regulates blood pressure • Sends blood to different areas of the body

6. Functions Continued • Provides movement of internal organs • Moves food through digestive tract • Enables bladder control • Causes involuntary actions • Reflex actions • Adjusts opening of pupils • Causes hair to stand on end: goosebumps.

7. Types of Muscle Tissue • There are three main types of muscle tissue • Skeletal(striated) • Cardiac(heart) • Smooth(visceral)

8. Comparison of Muscle Types Muscle Type Skeletal Cardiac Smooth Attached to bone Walls of internal organs + in skin Heart Location Movement of bone Movement of internal organs Beating of heart Function Control Mode Voluntary Involuntary Involuntary

9. Muscle Movement Flexor • ______- Muscle that bends the joint when contracted. • ________- Muscle that straightens the joint when contracted. • __________ muscleis short, firm, tight and thicker around. • _______ muscle is stretched, long, loose and thinner around. Extensor Contracted Relaxed

10. Interesting Facts About Muscles • Muscles are bundles of cells and fibers. • Muscles work in a very simple way. All they do is tighten up--that is, contract--and relax. • You have two sets of muscles attached to many of your bones which allow them to move. • There are 630 active muscles in your body and they act in groups. • Muscles can only pull. They never push.

11. The End!