1. Your Musculoskeletal System The skeletal system is a framework of bones and the tissues that connect to these bones. The muscular system is made up of all the muscles in the body, numbering around 650. Because these two body systems are so closely intertwined, they are often referred to as the musculoskeletal system. The musculoskeletal system supports your body and enables you to move.

2. What Do Muscles & Bones Do In The Body? Support. Bones are the support of your body- like the beams that support a building. Protection. Bones protect the soft parts of your body from injury. Movement. Muscles and bones move all your body’s parts

3. What Do Muscles & Bones Do In The Body? (cont.) Internal movement. Muscles move body organs that have no bones, such as your heart, intestines, and stomach. Blood cells. Tissue inside bones makes red and white blood cells for your circulatory system. Mineral storage. Bones store calcium and other important minerals.

4. Bones Adults have 206 bones in their body. Bones are hard on the outside and have spongy tissue inside. The spongy tissue produces the blood cells for the circulatory system. Bone tissue is alive and is made up of cells that die but then get replaced, especially while you are still growing. A joint is the point where two or more bones meet. Different joints move in different ways.

5. Connective Tissue Connective tissue joins bones to muscles and other bones. Cartilage is soft tissue that covers the ends of bones and supports certain structures (i.e. nose, ears). It allows joints to move easily, and cushions the individual bones of the spinal column.

6. Connective Tissue (cont.) Ligaments hold bones together at the joints of the body. The knee and the ankle, for example, are held together by strong ligaments. Tendons attach muscles to bones and move bones when muscles contract. The Achilles tendon (above the heel) is the largest tendon in your body.

7. Muscles Your body contains about 650 muscles. All muscles are classified as voluntary (meaning you can control them), or involuntary (meaning they function automatically). Muscles are further classified according to their type: skeletal, smooth, or cardiac.

8. Muscles (cont.) Skeletal muscles are voluntary- under your control. Smooth muscles (like the ones that line your stomach and intestines) are involuntary. Cardiac muscle tissue is also involuntary. Cardiac muscle tissue is special because it does not need outside [electrical] stimulation- it has its own internal pacemaker.

9. How You Move Muscles work by changing length. When stimulated by a nerve, muscle fibers contract, or shorten. If the muscle is a skeletal muscle, the contraction pulls along the bone the muscle is attached to. Muscles can only pull bones- they cannot push them. As a result, muscles must work in pairs to move body parts. When one paired muscle contracts, the second muscle extends, or lengthens. To move the body part back, the second muscle must contract while the first muscle extends.

10. Keeping Your Musculoskeletal System Healthy 1.Eat a well-balanced diet, including foods with calcium, phosphorus, & Vitamin D. Muscles need protein for growth and carbohydrates for energy. 2.Exercise safely. Warm-up & cool-down. 3.Practice good posture. 4.Get enough rest. Your muscles need rest between periods of exercise.