1. The Skeletal System

3. Functions of the Skeletal System:
Every movement is possible because of the muscles working with the bones – skeletal system.
Functions of the Skeletal System:
1. Anchor for body’s movement
2. Provides support
3. Protects soft organs inside the body.

4. Classification of Bones
Long bones – arms and legs
Short bones – feet and hands
Irregular bones – spine
Flat bones – ribs and skull

5. What are Bones Made Of??? living tissue
They have spaces inside – Bones are made of soft and hard material
allow blood nutrients to pass through

6. Two Types of Bone Tissue
Compact Bone – Outside of the bone -Supportive tissue of the body-Is the part we call the skeleton
Spongy Bone – Tissue inside the bone-Strong, but lightweight

7. Marrow and Blood Cells
Marrow – inside the spongy bone tissue, produces blood cells
The blood brings nutrients to the bone cells and carries waste materials away.

8. Two Main Divisions in the Skeleton
Axial Skeleton – Central part of the Skeleton
Forms the axis
Provides support and protection
Includes the skull, spinal column, ribs
Appendicular Skeleton – attached to the axis skeleton-Allows movement - Shoulder, legs, arms, knees, etc.

9. The Skeleton Changes as We Grow
Infancy – Skull is made up of several bones that have spaces between them – The spaces gradually grow together.
Childhood – Bone growth occurs at growth plates, a flexible, firm connective tissue. The length and shape of bones is determined by growth plates.
Adolescence – Bones stop growing at the end of adolescence – the growth plate becomes hard, then arms and legs stop growing and the skull plates fuse together.
Adulthood – As people age, more bone is broken down than is formed. Bones become less dense and can break more easily.

10. Joints Connect Parts of the Skeletal System
Joint – A place at which two parts of the skeletal system meet.
Three Types of Joints:
Immoveable – locks bones together like puzzle pieces. Ex: bones of skull
Slightly moveable – enables you to flex slightly. Ex: ribs connected to sternum
Freely Moveable – joints that allow your body to bend and to move. Ligaments hold the bones together at moveable joints.