The Skeletal System The Skeletal System Definition all

The Skeletal System

The Skeletal System • Definition: – all the bones in the body

The Skeletal System Function – forms an internal, living framework that • provides shape and support • protects internal organs • moves bones • forms blood cells • stores calcium and phosphorous compounds for later use

Bones • Made of layers of living tissue • Covered with a tough, tight-fitting membrane called the periosteum

Compact Bone • • • Directly under the periosteum Hard, strong layer Gives bones strength Contains deposits of calcium phosphate Contains bone cells and blood vessels

Spongy Bone • Located at the ends of long bones • Has many small, open spaces that make bones lightweight • Filled with a substance called marrow – yellow composed of fat cells – red produces red blood cells

Cartilage • Smooth, slippery, thick layer of tissue • Covers the ends of bones • Does not contain blood vessels or minerals • Flexible and acts as a shock absorber • Makes movement easier by reducing friction

Joints • Definition: – Any place where two or more bones come together

Joints • Kept far enough apart by a thin layer of cartilage so that they do not rub against each other as they move • Bones are held in place at joints by a tough band of tissue called ligament

Types of Joints • Immovable – Skull – Pelvis • Moveable – Pivot – Ball & socket – Hinge – Gliding

Types of Joints • Ball and Socket Joint • Bone with a rounded end that fits into a cuplike cavity on another bone http: //www. shockfamily. net/skeleton/JOINTS. HTML

Types of Joints • Pivot Joint • One bone rotates in a ring of another bone that does not move http: //www. funhousefilms. com/b-pivot 2. jpg

Types of Joints • Hinge Joint • Back-andforth movement like hinges on a door http: //www. shockfamily. net/skeleton/JOINTS. HTML

Type of Joints • Gliding Joint • One part of a bone slides over another bone http: //www. shockfamily. net/skeleton/JOINTS. HTML