1. The Skeletal System Kavitta Ghai, Shefali Mathrani, Rebecca Ryan

2. Main Functions  Protection & Support  Skeleton protects internal organs and fragile body tissues  Provides framework for body  Allows us to keep our shape  Blood cell formation  Red bone marrow produces red and white blood cells  Stores minerals and energy  Bone tissues stores calcium and phosphorus  When required, minerals are released into the blood  Yellow bone marrow stores chemical energy and fat  Aids movement  Works with muscular system to allow body to move

3. How It Works  Protection and Support:  Cranium protects brain and eyes  Ribs protect heart and lungs  Vertebrae protects spinal cord  Production of blood cells:  Red marrow produces blood cells, platelets and most white blood cells  Some white blood cells develop in yellow marrow  Cases of severe blood loss: body can convert yellow marrow to red marrow to increase blood cell production.  Movement:  Muscles attached to bones through tendons  Bones and muscles work together by impulses and signals  Nervous system signals muscle to contract  Muscle contracts, bone moves with it

4. What Are Bones?  Hard, whitish tissue making up the skeleton  Considered living organs  Made of epithelial tissue—the thin tissue that forms the outer layer of a body's surface, nerves, muscle tissue and connective tissue  Grow and change as your body mature

5. What Makes Up Bones  Periosteum: thin, dense membrane that lines the outer surface of bones and contains nerves and blood vessels to nourish bone  Compact Bone: smooth and very hard part of bone, blood vessels run through it  Cancellous Bone (Spongy Bone): looks like sponge because has large open spaces, not as hard as compact bone, protects bone marrow  Bone Marrow: produces blood cells and stores energy

6. Joints  Immovable Joints: connected by connective tissue, do not allow movement  Slightly Movable Joints: joined together by cartilage  Freely Movable Joints: joined by cartilage and cushioned cavities filled with synovial fluid

7. Types of Joints

8. Strengths  Muscles and bones enable body to move  Bones are strong because of calcium compounds  Marrow produces new blood cells and repairs old ones  Comprise only 18% of body weight

9. Weaknesses  Arthritis: disease of the joints, caused by destruction of cartilage between bones and joints  Scoliosis: abnormal curvature of the backbone, caused by disease that affects spine  Osteoporosis: disease of the bone, becomes thin so easy to fracture

10. Cures  Arthritis: Lifestyle changes, physical therapy, medication, and surgery  Scoliosis: braces or surgery  Osteoporosis: Proper diet, adequate calcium, medication, exercising

11. Weaknesses Cont.  Fractures: bone shatters  Torn ligaments: breakage of connective tissue which holds together bones and joints

12. Maintaining A Healthy Skeleton  Drink milk or take calcium supplements  Exercise; engage in weight-lifting  Maintain a healthy diet; orange juice, broccoli, fish, etc.  Keep teeth clean  Wear protection during sports

13. Interesting Facts  There are over 100 types of arthritis  Babies start out with 300-350 bones  There are 206 bones in the adult body  Scoliosis is more common in girls than boys

14. Review Questions  What part of the bone produces new blood cells as well as repairing damaged ones?  What are the three types of joins?  What covers and protects our major organs?  What kind of tissue do bones mainly consist of?  How many bones are in an adult body?  Name one way we can maintain the skeletal system.