Bone Growth

1. Bone Growth

2. Early in development, the human fetus is made entirely of cartilage.

3. Ossification • The process of turning soft cartilage into hard bone. • Mineral deposits replace the cartilage.

4. Ossification • In long bones (arms and legs), ossification begins at the center and moves toward the ends.

5. Ossification • At birth, cartilage remains in the skeleton, including at the end of long bones. • This cartilage will grow as the long bones grow, so the skeleton can increase in length.

6. Ossification • In the late teens/early 20’s, all the cartilage becomes replaced by bone. • This is called skeletal maturity. • No further growth in length is possible.

7. Bone Formation through X-Rays

8. Bone Formation through X-Rays

9. Bone Anatomy Bone Marrow Spongy Periosteum Compact Bone

10. Bone Marrow • Red Marrow- Makes red blood cells, platelets, most white blood cells. • Yellow Marrow- Makes only white blood cells. (Only found in adult bones)

11. Skeletal Disorders • Giantism • Acromegaly • Pituitary Dwarfism • Osteoporosis • Osteomalacia • Fibrodysplasiaossificansprogressiva (FOP) aka Stone Man Syndrome

12. Giantism • Hypersecretion of Growth Hormone during childhood. • Excessive Growth

13. Acromegaly • Hypersecretion of Growth Hormone as an adult. • Overgrowth of face, feet, hands.

14. Pituitary Dwarfism • Deficiency of Growth Hormone • Short long bones

15. Osteoporosis • Bone is degraded faster than it can be replaced. • Results in porous bones. • Fractures in vertebrate and femur become common.

16. Osteomalacia • “Soft bones”- lacking minerals • In childhood, called “Rickets”- more detrimental because bones are still growing.

17. Fibrodysplasiaossificansprogressiva (FOP) • AKA Stone Man Syndrome • Bone replaces muscles, tendons and ligaments. • Ossification spontaneously or when injured.