The Skeletal SystemEvery movement is possible because

of the muscles working with the bones – skeletal system.

Functions of the Skeletal System:

1. Anchor for body’s movement2. Provides support3. 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 boneSupportive tissue of the

bodyIs the part we call the skeleton

Spongy Bone – Tissue inside the boneStrong, 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 axisProvides support and

protectionIncludes the skull, spinal column, ribs

Appendicular Skeleton – attached to the axis skeleton.

Allows movementShoulder, 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 skullSlightly moveable – enables you to flex

slightly. Ex: ribs connected to sternumFreely 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.