1. The Skeleton

2. Functions ► Support- provides a framework for muscles and organs. ► Protection of vital (necessary) organs. ► To make new blood. ► Storage of some energy sources

3. Structure ► Inside is lightweight but strong spongy bone. ► Marrow found in center. ► Outside composed of super strong covering of compact bone  releases calcium to help nerve conduction and muscle contraction.

4. Marrow ► Found on the inside of most bones. ► Red marrow: produces red blood cells (to carry oxygen). ► Yellow marrow: stores energy in form of fat.

5. Composition ► 40% minerals – calcium, phosphorus ► 30% Living tissue, cells, blood vessels ► 25% water ► Can withstand stresses of 24,000 pounds per square inch (4 times that of steel or reinforced concrete!)

6. Them Bones ► Funny Bone – not actually a bone, but a nerve located along the humerus (upper arm bone). ► Largest bone – Femur (upper leg) ► Smallest bone – Stirrup (stapes) (found in the ear – 1/10 of an inch!) ► 1 out of every 20 people has an extra rib (most commonly found in men)

7. Constant Change of the Skeleton ► Newborns start out with 275-350 bones. ► By adult age down to 206 due to bones fusing together. ► Last to fuse is the collarbone which happens between the ages of 18-25. ► Skeleton constantly rebuilds itself – you grow the equivalent of a new skeleton every seven years.

8. Adult bone distribution ► Skull – 22 ► Ears – 6 ► Vertebrae – 26 ► Sternum – 3 ► Throat - 1 ► Pectoral girdle – 4 ► Arms and hands – 60 ► Hips – 2 ► Legs and feet – 58 ► Ribs - 24