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

SpongyBone Marrow

Compact BonePeriosteum

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.