2. The Body’s Support Structure: The Skeleton

3. Functions of the skeleton: o Provides shape and support o Enables you to move o Protects your internal organs o Produces red blood cells o Stores materials like calcium until your body needs it o Provides shape and support o Enables you to move o Protects your internal organs o Produces red blood cells o Stores materials like calcium until your body needs it

4. Bone Strength: Some Facts  Bones are strong because they are made of tightly packed minerals like calcium and phosphorus but also so lightweight-they only make up 20% of an adult’s body weight.  They can absorb more force without breaking than granite or concrete.

5. Bone Growth oBecause bones are living tissue they grow as you do. oThe more you exercise, the stronger they grow. oBroken bones heal by growing new tissue.

7. Bone Structure:  The outermost layer is a thin tough layer called the outer membrane (or periosteum).  Next is a layer of hard compact bone.  Inside this is a layer of spongy bone which makes it lightweight but strong (from the minerals phosphorus and calcium).  Finally, the innermost layer is marrow-red (produces red blood cells) or yellow (which stores fat).

8. Bone Formation: Bone Formation: Most of an infant’s skeleton is cartilage, a soft, flexible connective tissue. This is replaced over time by bone, except for at the end of bones. This cartilage acts as a cushion between joints. Most of an infant’s skeleton is cartilage, a soft, flexible connective tissue. This is replaced over time by bone, except for at the end of bones. This cartilage acts as a cushion between joints.

9. JointsJoints oJoints are places where two bones are joined together or meet. o2 types: immovable joints (which don’t allow movement) like your skull) or moveable joints which allow movement (like your elbow). o4 kinds of moveable joints: Hinge (elbow); Ball & Socket (hip) ; Gliding (ankle); and Pivot (neck). oJoints are places where two bones are joined together or meet. o2 types: immovable joints (which don’t allow movement) like your skull) or moveable joints which allow movement (like your elbow). o4 kinds of moveable joints: Hinge (elbow); Ball & Socket (hip) ; Gliding (ankle); and Pivot (neck).

10. Taking Care of Bones  Eat a balanced diet.  Regular exercise causes bones to grow stronger  As people age, mineral loss can lead to osteoporosis, where bones become fragile. A diet rich in calcium can prevent this disease.

11. Marrow Spongy bone Outer membrane