1. Chapter 9 Section 3 04-13-04

2. Muscular System: is made up of muscles and the connective tissue that attaches the muscles to the bones 3 Types of Muscles: 1) Smooth: found in the digestive tract and the walls of blood vessels 2) Cardiac: found only in the heart 3) Skeletal: muscles that surround the bones and protect inner organs Types of muscle action: 1) Voluntary: under your control 2) Involuntary: not under your control

3. Making Connections: Tendons: connect the muscles to the bones Working Together: Flexor: Makes a muscle bend Extensor: When a muscles straightens part of your body There are more than 600 Muscles in the body.

4. Keeping Muscles Fit: Aerobic Exercise: (ex. Walking, running, swimming) helps strengthen you heart and give your muscles endurance. Resistance Exercise: (weight lifting) strengthens your skeletal muscles Dangers of Steroids: Anabolic Steroids: powerful drugs that resemble testosterone (male sex hormone). Effects: 1) Threatens the heart, liver, and kidneys 2) Can cause high blood pressure 3) Can cause the bones to stop growing