Understand the process of bone growth and resorption MT: Skeletal System

What is different between the two bones in the next picture?

Ossification Is the forming of new bone

Resorption Is the breaking down of old bone

Osteoblast & Osteoclast’s Roles in Ossification & Resorption Osteoblasts in periosteum, build new bone around the periosteum (outside of bone) At the same time, osteoclasts are breaking down bone in the endosteum

Results in… A bone with a larger diameter and larger medullary cavity Allows growth in both length and diameter of bone Allows a change in shape and size of medullary cavity Keeps Ca2+ levels in body balanced

-Increased medullary cavity -Wider diameter -Longer

Rate of Ossification/Resorption Child: ossification occurs faster than resorption, thus bone growth = Bone growth Ossification Resorption

Rate of Ossification/Resorption Adulthood: ossification occurs at the same rate as resorption, thus no overall bone growth = Same size bone Ossification Resorption

Rate of Ossification/Resorption 40 yrs and older: ossification occurs at a slower rate than resorption, thus bone depletion = reduced bone size Ossification Resorption

Prevention How much calcium do I need? Children and teenagers between the ages of 9 and 18 should aim for 1,300 mg per day. Each 8-oz glass of milk and each cup of yogurt has about 300 mg of calcium. Adults 19 to 50 years of age should aim for 1,000 mg per day. Adults 50+ need 1,200 mg per day. Exercise stresses the bones and keeps them working to build strong bones Proper intake of Ca2+ in diet Don’t get old!