The skeletal system consists of 206 bones that provide structure, protect organs, allow movement, store minerals, and form blood cells. There are five major functions of the skeleton. Bones are composed of compact bone, spongy bone, marrow, cartilage, and ligaments that connect bones at joints, which can be movable or immovable. The four types of movable joints are pivot, ball and socket, hinge, and gliding joints. Arthritis is a common joint problem that damages joints through conditions like osteoarthritis and rheumatoid arthritis.

1. THE
SKELETAL
SYSTEM

3. 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

4. • 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

5. 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. 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. 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

10. * 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.

11. • 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

13. 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…)

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

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

16. 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

19. Look
alive, lazy
bones!