1. Skeletal System
Composed of the body’s bones and associated ligaments, tendons, and cartilages.
Functions:
Support
Protection
Movement
Reservoir for minerals and adipose tissue
Hematopoiesis
All blood cells are made in the marrow of certain bones.

2. Bone Classification There are 206 named bones in the human body.
Each belongs to one of 2 large groups:
Axial skeleton
Includes the bones of the skull, vertebral column, and rib cage.
Appendicular skeleton
Bones of upper & lower limbs and the girdles (shoulder bones and hip bones) that attach them to the axial skeleton.

3. Bone Classification Femur  4 types of bones: Carpal Bones Long Bones
All bones of the limbs except for the patella (kneecap),
and the bones of the wrist and ankle.
Short Bones
Roughly cube shaped.
Bones of the wrist and the ankle.
Carpal Bones

4. Bone Classification Types of bones: Flat Bones Irregular Bones
Thin, flattened, and usually a bit curved.
Scapulae, sternum, (shoulder blades), ribs and most bones of the skull.
Irregular Bones
Have weird shapes
Vertebrae, hip bones, 2 skull bones.
Sternum
Sphenoid Bone

5. Bone is an extremely dynamic tissue!!!!
All bones consist of a dense, solid outer layer known as compact bone and an inner layer of spongy bone.
Bone is an extremely dynamic tissue!!!!
Above: Note the relationship btwn the compact and spongy bone.
Below: Close up of spongy bone.

6. Note the gross differences between the spongy bone and the compact bone in the above photo.

7. Bone Structure Bone tissue consist of 3 cells. Bone cells: Osteoblasts
Bone-building cells.
2. Osteocytes
Mature bone cells.
Responsible for maintaining the bone tissue
Osteoclasts
Breakdown bone tissue
The blue arrows indicate the osteoblasts. The yellow arrows indicate the bone matrix they’ve just secreted.

8. Why are osteoclast bigger than osteoblast?

9. Bone Marrow There are 2 main types: red & yellow.
Red bone marrow = blood cell
Red bone marrow looks like blood but with a thicker consistency.
Notice the red marrow and the compact bone

10. Distribution of Marrow
Note the compact bone on the bottom and marrow on the bottom.
In a child, nearly every bone is filled with red bone marrow.
In young to middle-aged adults, bones are filled with fatty yellow bone marrow gives lots of energy.
In adults, red marrow provides the ability to repair bones tissue and aids in immunity.

11. Fractures
Despite its mineral strength, bone may crack or even break if subjected to extreme loads, sudden impacts, or stresses from unusual directions.

12. Fracture Types
Fractures are often classified according to the position of the bone ends after the break:
1. Open (compound)  bone ends break through the skin.
2. Closed (simple)  bone ends don’t break through the skin.
3. Comminuted  bone breaks into 3 or more pieces. (elderly)
4. Greenstick bone breaks incompletely. One side bent, one side broken. (children)
5. Spiral  ragged break caused by excessive twisting forces. Sports injury/Injury of abuse.
6. Impacted  one bone fragment is driven into the marrow space.

14. What kind of fracture is this?
It’s kind of tough to tell, but this is a _ _ _ _ _ _ fracture.

15. What about the above x-ray is indicative of rickets?
Clinical Conditions
Rickets
Children's form
Signs include bowed legs, and deformities of the pelvis, ribs, and skull.
Due to calcium and vitamin D deficiency.
What about the above x-ray is indicative of rickets?

16. Clinical Conditions Osteoporosis
Disease in which osteoclasts are breaking down bone tissue faster than osteoblasts can build.

17. Clinical Conditions Gigantism excessive skeletal growth (evenly)
Acromegaly
Imbalance growth such as the bones of the face, feet, and hands.
Pituitary dwarfism
Extremely short long bones and maximum stature of 4 feet.