Bone Growth Early in development the human fetus

Bone Growth

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

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

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

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.

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.

Bone Formation through X-Rays

Bone Formation through X-Rays

Bone Anatomy Bone Marrow Spongy Periosteum Compact Bone

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)

Skeletal Disorders • • • Giantism Acromegaly Pituitary Dwarfism Osteoporosis Osteomalacia Fibrodysplasia ossificans progressiva (FOP) aka Stone Man Syndrome

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

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

Pituitary Dwarfism • Deficiency of Growth Hormone • Short long bones

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

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

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