THE SKELETAL

SYSTEM

1. Skeleton - a framework of living bones that supports your body

2. Skeletal system – all the bones in your body make up the skeletal system

3. There are 206 bones in the human body

• The skeleton has five major functions:

1) Gives shape and support to your body

2) Protect your internal organs

3) Help major muscles move

4) Form blood cells

5) Store calcium and phosphorous

4. The periosteum is the tight-fitting membrane that covers living bone.

5. Compact bone is the hard layer of bone directly under the periosteum.

6. Spongy bone is found at the ends of long bones and has many small, open spaces to make bones more lightweight.

7. Marrow is a substance found in the spaces in long bones. Marrow can be yellow (composed of fat cells) or red.

*Red marrow produces red blood cells.

7. Cartilage is a smooth, thick layer of tissue that covers the ends of bones.

- cartilage is flexible; it acts as a shock absorber and makes movement easier

8. A joint is any place where two bones come together

9. Ligaments are the tough bands of tissue that hold joints in place

* Joints are generally classified as moveable or immoveable.

10. An immoveable joint allows little or no movement. The joints of the bones in the skull are immoveable.

• There are 4 types of moveable joints:

1) Pivot joint – one bone rotates in the ring of another bone; the bones that allow you to turn your head are pivot joints

2) A ball and socket joint consists of a bone with a rounded end that fits into a cuplike cavity in another bone. (hips, shoulders…)

3) A hinge joint moves back and forth like a door hinge. (elbows, knees, fingers…)

4) A gliding joint is a joint in which one part of a bone slides over another. (wrists, ankles…)

11. Arthritis is the most common joint problem. - the word arthritis describes more than 100 different diseases that can damage joints

- osteoarthritis is caused by a breakdown of cartilage

- rheumatoid arthritis is a condition in which the body’s immune system destroys its own tissues

Look alive, lazy bones!