1. Skeletal System
Chapter 7

3. Increase your understanding…
Acetabul-
Ax-
-blast
Carp-
-clast
Condyl-
Corac-
Fov-
Glen-
Inter- vs. intra-
Meat-
Poie-
[vinegar cup] acetabulum
[axis] axial skeleton
[Budding] osteoblast
[wrist] carpals
[break] osteoclast
[knob] condyle
[a crow’s beak] coracoid process
[pit] fovea capitis
[joint socket] glenoid cavity
Between vs inside
[Passage] auditory meatus
[make/produce] hematopoiesis

4. Bones….. A dynamic, living tissue About 30% of bone is living tissue
About 45% of bone is mineral
Finally, about 25% of bone is made up of water.

5. Bones, bones, bones!
There are 206 bones in the human body, making up our skeletal systems.
What does it do??
provides a strong framework
It supports and protects
It provides a point of attachment
certain bones, connected at flexible joints, form a combination of levers that allow coordinated movement

6. Types of Bones…
Long bones
Flat bones
Short bones
Irregular bones

7. Bone Structure Epiphysis Diaphysis Periosteum Compact bone Spongy bone
Medullary cavity
Endosteum
Marrow

9. How are bones made?
Bone tissue is made and maintained by several types of cells:
Osteoblasts
Osteocytes
Osteoclasts
**Homeostasis of BONES!**

10. Bone Structure and Development
There are lots of good videos online to supplement learning… here are a few for you to check out:

11. Intramembranous bone formation
Increased vascularity of tissue.
Active proliferation of mesenchymal cells.
Osteoblasts begin to lay down osteoid. 
Osteoblasts either retreat or become entrapped as osteocytes
The osteoid calcifies to form spicules of spongy bone.
Bone remodeling occurs. 

12. Endochondral Bone formation

13. Endochondral bone formation
This type of ossification involves the replacement of a cartilaginous model by bone
Primary ossification center.
Bone collar. 
Periosteal buds.
Secondary ossification centers.

14. In other words… A baby has very soft bones made up of cartilage.
As the infant grows, the cartilage is replaced by calcium (ossification).
When a person reaches the age of 20 or so, the bones stop getting longer or bigger, but there is still a lot of growing going on.
Old bone cells dissolve and are replaced by new bone cells.

15. Question to think about..
A child sustained serious injuries in a recent automobile accident. Injury to the epiphyses of various bones was discovered. Why are these injuries of special concern?

16. Bone Density Density is a ratio of mass to volume.
Example: Suppose that a box has a mass of 30 grams and a volume of 6 cubic centimeters.
Find the density:
m = 30 g
v = 6 cm3
step 1) D = m/v
Step 2) D = 30 g/6 cm3
step 3) D = 5 g/ cm3

17. Why do we care
Bone fractures… p131

18. Osteoporosis

19. Bone functions Support Protection Body Movement Blood Cell formation
Storage of Inorganic salts

20. Are your TEETH bones?
Teeth are not really bones. Bones, unlike teeth, are wrapped in a layer of cells called the periosteum. The periosteum and a few other cell types allow bones to grow and be remodeled over time. Teeth are unable to do this, which is why we have to take care of them.
Teeth are made up of four different layers of tissue:
1.Enamel is the hard, white covering. Enamel protects the tooth from the wear and tear of chewing. The enamel on your teeth is the hardest substance in your body.
2. Dentin is below the enamel on your teeth. It's a yellow bone-like material that's softer than enamel and carries some of the nerves that tell you when something is going wrong inside your tooth.
3. Pulp is the center of the tooth. It's a soft tissue that contains blood vessels and nerves. The pulp is how the tooth receives nourishment and sends signals to your brain.
4. Cementum is what covers most of the root of the tooth. It helps to attach the tooth to the bones in your jaw. A cushioning layer called the Periodontal Ligament sits between the cementum and the jawbone. It helps to connect the two.