physics of skeleton

Bone has at least six functions in the body
1.Support
2. Locomotion
3. Protection
4. Storage of chemicals
5. Nourishment
6. Sound transmission (in the middle of ear)

• The body s muscles attached to the bone through tendons and ligaments (the system of bones plus muscles support the body)
• Bone joints permit movement of one bone with respect to another.
• The skull protect the brain and several of the most important sensory organs (eye and ears), the ribs form protective cage for heart and lungs
• Bones acts as chemical bank for storing element for future use.
Ex. Minimum calcium is needed in the blood if the level falls too law calcium causes parathyroid glands to release more para hormone into blood and this causes bones to release the needed Ca.
The teeth are specialized bones can cut food and serve nourishment.
Three smallest bones of the body are oscillate in middle air to provide matching system for converting sound vibration in air to sound vibration in fluid in cochlea. They are the only bones that attain full adult size before birth.


What is the bone made of?

Bone consist of two different materials plus water, collagen (organic fraction 40% of the bone weight, 60% of its volume and bone mineral (inorganic 60% of its weight ,40% its volume).
There are large percentage of Ca in the body, it has much heavier nucleus than most elements of the body, it absorbs x-ray much better than surrounding soft tissue.
This the reason x-ray show bones so well, using x-ray scattering indicates that bone mineral crystals are rod shaped of diameter 20-70A? and length 50-100A?