Muscles bones and muscles. Bones and muscles work together to - PDF document

Like a machine, your body consists of many parts that move. • Those parts are your Muscles bones and muscles. Bones and muscles work together to provide a structural framework for movement. Muscle Action - Voluntary Muscle Action – Involuntary • Voluntary means that • Involuntary means you do not control the you can control it. movement. • Most of the time, • The beating of your heart and movement of skeletal muscles are skeletal muscles are your digestive tract are both examples of in your digestive tract are both examples of in involved in voluntary voluntary muscle action. muscle movement. • When you lift an object, it is voluntary . The major function of the muscular You can voluntarily blink your eyes; system is to move bones. however, sometimes blinking your eyes is involuntary. • Muscles and bones work in coordination with your nervous system to move your body on demand. y • The muscular system also provides support and protection for your organs. 1

Tendons • Tendons attach the muscles to bones Skeletal, smooth, cardiac muscle, and allowing muscles and bones to work in coordination with your nervous system to tendons make up the muscular move your body on demand. system. y The three types of muscle in the muscular system are skeletal, cardiac, and smooth. Bundles of fibers are bound together by Skeletal muscles are made of skeletal connective tissue. muscle tissue. • Blood vessels and • Skeletal muscle tissue is nerves run through made up of thousands of the connective tissue. cylindrical muscle fibers y often running the entire length of the muscle. 2

Muscle fibers contain long muscle cells each with thousands of mitochondria for energy. Label the muscles • During a muscle contraction, a complex reaction p causes muscle fibers to shorten. • When the muscle relaxes, muscle fibers return to their original position. Muscles usually work in pairs called flexors and extensors. • If a muscle bends part of your body, it is called a flexor. • If a muscle straightens part of your body, it is • Flexor and extensor called an extensor. pairs provide almost all the movement of your skeleton. During a muscle contraction, the muscle Muscles require movement and exercise fibers get shorter. to remain strong. • Resistance exercise requires muscles to overcome resistance (weight). • Resistance exercise increases muscle size and strength. 3

Aerobic exercise like running, swimming laps, and cycling strengthens the strengthens the heart and increases the endurance of skeletal muscle. 4