Skeletal System Notes

Textbook Online


Functions: (5)

1. Framework- gives us the structure to support and shape us as we are.

2. Protects our vital organs.

3. Allows attatchment of muscles so that we can move.

4. Production of blood cells. Red marrow produces 2 billion r.b.c. per second, w.b.c. are produced slower. As an adult the production occurs in the end of the femur, pelvic bone and sternum.

5. Storage of calcium and phosphorus. These elements make the bone hard

Structure: Bones are different shapes and designs depending on its job and location. Processes are bumps and grooves that allow ligaments and muscles to connect and allow blood and nerve vessels to pass through.

Bone is living while inside of a living body. It is made of cells that need nutrients and uses energy.

bone development- ossification: osteoblasts build up bone. osteoclasts break down bone tissue and release calcium and r.b.c.

*periosteum- thin membraned sheeth that covers the bone. contains blood vessels and nutrients.

*compact bone- hard shaft of long bones, very dense. contains bone cells, blood vessels and protein.

*spongy bone- at the ends of long bones, open porous honeycomb like. light weight.

*marrow- soft inner part of the bone that contains blood vessels and fat cells. red marrow produces blood cells and yellow stores lipid.            

Ligaments: strong elastic connective tissue that holds bone to bone.

Cartilage: connective tissue that is flexible. it has no blood velles or minerals. it is at the ends of bones and absorbs shock and reduces friction. it works as a cushion. it can wear away and is called arthritis. 



JOINTS: the place that two or more bones join (meet). ligaments connect bone to bone. 

Fibrous: no cavity (space)

*immoveable- fused in place. Example: skull

*slightly moveable- bending and twisting, little movement of bones. Example: vertebrae

Synovial: have joint cavity (space). freely moveable.

*ball and socket- rotating. greatest range of motion. Example: shoulder and hip

*hinge- movement in one direction, forward and backwards (door hinge). one bone concave and the other convex. Example: elbow and knee

*pivot- Twisting, rounded ends, the rotation of one bone around another. Example: top two vertebrae (atlis and axis)

*gliding- rotating over one another, two surface slide. Example:  wrist and ankle

*saddle- both bones concave and convex. Example: hand

Synovial fluid: lubricates the joints so they move properly. In the elderly, it dries up causing their bones to creak.