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.

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

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

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

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.

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.

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.

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.

Ligaments & Tendons A ligament is a strong, flexible band. A ligament links or connects bones together. A tendon is a cord made of tough, white tissue that attaches muscles to bones. A tendon connects muscles to bones.