1. Skeletal System

2. Shapes of Bones Long Bones: Longer than they are wide
Have a shaft with a head at both ends
Made of mostly compact bone.
Found in the limbs of the body.

3. Shapes of Bones Short Bones: Generally cubed-shaped
Contain mostly spongy bone
Found in the wrists and ankles

4. Shapes of Bones Flat Bones: Thin, flattened, and usually curved.
Two thin layers of compact bone covering spongy bones.
Found in the skull, ribs, and sternum

5. Shapes of Bones Irregular Bones:
Bones that do not fit into the previous categories
Vertebrae and hip bones.

6. Structure of a Long Bone
Epiphyses: Ends of the long bone. Made of compact and spongy bone.
Articular Cartilage: Slippery cartilage that covers the epiphyses. Provides a smooth surface at the joint for movement.

7. Bone Marrow
In adults, the shaft of long bones store adipose called yellow marrow. The only place to find red marrow is in the cavities of spongy flat bones and the epiphyses of some long bones.**
-The bones of most young children are made of hyaline cartilage. As you grow into an adult, the cartilage hardens into bone by a process called ossification.

8. Making & Destroying Bone
osteoblasts: bone-forming cells (make bone) Bone Building
osteoclasts: bone-destroying cells. Activated when calcium levels fall below homeostatic levels