1. The Skeletal System
The skeletal system is the framework of your body and has 5 major functions:

2. Functions of Skeletal System:
The skeletal system gives shape and support to your body.
Bones protect your internal organs.
Major muscles are attached to bone and help them move.
Blood cells are formed in the center of many bones in the soft tissue called marrow.
Calcium and phosphorous are stored in the skeleton for later use. Calcium and phosphorous make bones hard.

3. Bone Structure Spongy bone
is located toward the ends of long bones. It has many open spaces that make the bones lightweight and contain marrow.
Compact bone
gives bones its strength. Bone cells and blood vessels are found here.
Bone Marrow:
Red marrow produces blood cells. Yellow marrow is composed of fat cells.

4. How the skeletal system works
Cartilage:
a smooth, slippery, thick layer of tissue that covers the end of bones. Cartilage acts as a shock absorber and reduces friction between the bones.
Joints:
Anywhere two or more bones come together. Can be movable or immovable.
Ligament:
tough band of tissue which holds bones together.

5. Types of Joints Ball and Socket Joint Found in your hips &
shoulders. This joint allows for freedom of rotation as well as back-and-forth movement in all planes.  It allows for the most freedom in movement of any other joint. 

6. Types of Joints
Hinge
Found in the elbow and knee. Hinge joints offer ease in movement, but only provide for movement in one plane (no twisting, no sliding side-to-side). It allows for extension and retraction only.

7. Types of Joints
Pivot
This joint is one where one bone spins around on another bone.  This joint is found in our neck and forearms.

8. Types of Joints Gliding Joints:
Although these joints appear to offer a lot of flexibility in movement direction, they do not offer a great distance in movement.  But they can move in many directions and they can rotate. These joints can be found in the wrist and ankle.

9. Types of Joints Immovable Joints
Immovable joints allows for little or no movement. The joints of the bones in your skull and pelvis are examples of immovable joints.

10. Connections to other systems
The skeletal system works with the muscular system to allow movement in the body. When the muscles contract this causes the bones in the skeletal system to move.
Red blood cells are made in the bone marrow of the long bones in the body. This is how the skeletal system works with the circulatory system.

11. Diseases of the Skeletal System
Arthritis
pain, stiffness and swelling of the joints
Osteoarthritis
When cartilage breaks down from years of use
Rheumatoid Arthritis
ongoing condition in which the body’s immune system tries to destroy its own tissues.