1. Skeletal System

2. Major Functions of the Skeletal System
1. Provide shape and support.
2. Enables you to move
3. Protects your organs
4. Produces blood cells
5. stores minerals and other materials until your body needs them.

3. Shape and Support Skeleton determines the shape of your body.
The backbone or vertebral column is the center of the skeleton
32 small bones or vertebrae make up the backbone
Vertebral column is flexible and able to bend.

4. Movement & Protection Your skeleton allows you to move
Muscles attach to the bones, pulling on them to make body move.
Bones protect many of the body organs
Example: the skull protects the brain and the rib cage protects the heart and lungs.

5. Production & Storage of Substances
Long bones of your arms and legs produce certain blood cells (red and white)
Bones store minerals such as calcium and phosphorus and release them when the body needs them.

6. Bone Structure (1)
Bones are complex living structures that undergo growth and development
A thin tough outer membrane covers the bone
Beneath the outer membrane is a layer of compact bone (hard and dense, but not solid – it is filled with holes and has small canals for blood vessels nerves.

7. Bone Structure (2) Inside the compact bone is a layer of spongy bone.
It has many small spaces, is light weight, but strong.
Spongy bone is also found at ends of bones.

8. Bone Structure (3)
In the spaces of many bones there is a soft connective tissue called Marrow
Two types of Marrow:
1. Red
2. Yellow
Red Marrow produces most of the body’s blood cells
Yellow Marrow stores fat that can serve as an energy reserve

9. Bone Strength Structure of bones make it both strong and light weight
20% of adults average body weight is bone
Made up of minerals: Calcium & Phosphorus (similar to what is found in most rocks)

10. Bone Growth
Bones are alive (contain cells and tissues such as blood and nerves)
Bones grow in response to stress
Example: when playing sports, some of your bones absorb the force of your weight. They respond by getting stronger, making new bone tissue.
Example: new bone may form after an accident, when you break a bone. The new tissue forms to fill in the gap between the broken ends.
Break in
Femur

11. Bone Development As an infant, most of your skeleton is cartilage
Cartilage is a strong flexible tissue.
Over time the cartilage is replace by solid bone, usually complete by the time you stop growing.
Not all cartilage is replaced in adults. Many joints contain cartilage, protecting the ends of bones. (ears and the end of the nose is also cartilage)

12. Joints A joint is a place where two bones come together.
Joints allow the bones to move in different ways
Two types of Joints:
1. Immovable
2. Movable Joints

13. Immovable Joints Allows little or no movement
Example: the bones of the skull

14. Movable Joints Most of the joints are of this type
Allow the body to move in a wide range of movements.
Bones in movable joints are held together by strong connective tissue called ligaments
Four types of Movable Joints:
1. Hinge
2. Ball-and-socket
3. Pivot
4. Gliding

15. Hinge Joint
Allows forward or backward motion
Example: elbow

16. Ball-and-Socket Joint
Allows the greatest range of motion
Example: shoulder
(the ball-and-socket joint allows you to swing your arm freely in a circle)
Example: Hips

17. Pivot Joint Allows one bone to rotate around another. Example: Neck
Allows you to turn your head from side to side.

18. Gliding Joint Allows one bone to slide over another
Example: wrist or ankle
Enable you to bend and flex as well as make limited side to side motions

19. Taking Care of Your Bones
Healthy bones depend on a combination of:
A Balanced Diet
EXERCISE!!
Balanced Diet:
Foods high in calcium & phosphorus
Dairy products
Green leafy vegetables
Drink lots of water
Exercise:
Weight bearing activities (running, lifting) help bones grow stronger and more dense.

20. Student X-Rays
Right Wrist

21. Right Wrist