Notes- The Skeletal System

Functions I. 5 functions of the skeletal system A. Gives shape and support to your body. B. Bones protect internal organs 1. The rib cage, sternum, and vertebrae protect the heart and lungs. 2. The cranium protects the brain. C. Major muscles attached to bones.

Functions D. Blood cells are formed in the red marrow of some bones. E. Major amounts of calcium and phosphorus are stored. These elements make bones hard. Notice the red marrow and the compact bone

Parts of bones II. Parts of bones 206- 214 bones in your body. Classified by their shape. (long, flat and short)

Parts of bones C. Parts Periosteum a. Tough, tight – fitting on the outside of the bone. b. Small blood vessels carry nutrients into bone. c. Also important in growth and repair of bone

Parts of bones 2. Compact bone Contains bone cells, blood vessels, calcium, phosphorus, elastic fibers Elastic fibers keep bones from being too rigid, brittle, or easily broken

Disorders c. Rickets and Osteoporosis are two disorders caused by lack of minerals Osteoporosis www. Ihealth

Parts of bones 3. Spongy bone Found towards the end of long bones Has lots of open spaces which cause bone to be light weight.

4. Marrow Cavity In center of long bones Filled with fatty tissue called marrow Produces 2-3 million red blood cells per second Produces white blood cells also

Parts of bones 5. Cartilage Thick , smooth layer over bone’s ends No blood vessels or minerals Flexible, absorbs shock, makes movement easier

Bone Development III. Bone Development Before birth, our skeleton is cartilage

Bone Development B. Osteoblast (bone- forming cells) replace cartilage. C. Osteoclast break down bone and release calcium and phosphorus into your bloodstream. The blue arrows indicate the osteoblasts. The yellow arrows indicate the bone matrix they’ve just secreted.

Fractures IV. Fractures A. Break in a bone

Fractures B. Types of fractures Simple : The bone has broken but the ends do not break through the skin. Compound: Broken ends of bone stick out through the skin.

Name the Fracture It’s kind of tough to tell, but this is a _ _ _ _ _ _ fracture. What kind of fracture is this?

Joints V. Joints Place where two or more bone meet. Ligaments- tough band of tissue that holds bones together at joints Types of joints Immovable Allows little or no movement Examples: pelvis and skull Movable a. Allows body to make a wide range of movements

Joints b. Types Pivot – head and arm (elbow) Ball and socket- hip and shoulder Hinge- knee, arm and fingers (conyloid) Gliding- wrist, ankle and vetebrae Immovable / Fixed joint – skull (cranium) Static. How stuffworks.com

Hinge joint and pivot joint

Know the parts of a skeleton Posterior View Frontal View