Skeletal System

Organization of Living things Cells Tissues Organs Organ Systems Organism

What is a skeleton? A SKELETON is a framework. The adult human body is made up of 206 bones Babies have about 350 bones.

functions of the skeletal system: Provides shape Provides support Allows for movement Protects vital organs Produces and stores needed substances like blood (makes) and calcium (stores)

Parts of the skeletal system joints: Joint – allows bones to move in different ways. Ligaments – connective tissue that connects bone to bone. Cartilage – connective FLEXIBLE tissue that covers the ends of bones and acts as a cushion. Knee Joint

2 categories of joints: Immovable Joints – allows little or no movement (ex: bones in the skull) Movable joints – allow movement 4 types: Hinge Joint - forward and backward movement (ex: knee, fingers, toes) Ball and Socket Joint – allows circular movement and the greatest range of motion (ex: shoulder, hip) Pivot joint – allows one bone to rotate around another (Elbow) 4. Sliding joint-allows one bone to slide over another (ex: wrist and ankles)

Bones…..the Organ: Bones are organs made up of many different types of tissues. Long Bone Anatomy: 4 layers Periosteum – outer layer of the bone, contains blood vessels and nerves Compact Bone – next to periosteum, hard and dense Spongy Bone – has many small spaces that help to make bones lightweight Marrow – soft connective tissue found on the inside of bones Red Marrow: produces some of the body’s blood cells Yellow Marrow: stores fat that can serve as an energy reserve

Continued: Bone Strength – bone structure makes them both strong and lightweight. Bones are stronger than concrete or granite rock!! Bone Growth – bones continue to “grow” make new bone tissue.

Bone health A combination of a balanced diet and regular exercise are important for a lifetime of healthy bones. Healthy Diet – important nutrients (calcium and phosphorus)

EXERCISE Weight bearing activities help bones grow stronger and more dense (ex: running, lifting weights, skating, dancing)

Skeletal system disease and injuries: Diseases: Osteoporosis – bodies bones become weak and break easily. More common in older women. Prevention begins early.

Continued: Arthritis – a disease of the joints in which cartilage breaks down.