BONE FORMATION, GROWTH, AND REPAIR NOTES

Osteogenesis: Formation of Your Bones Compare the two types of bone formation. Endochondral Ossification

Ossification: The process of forming bone. The cartilage or membranes are ultimately replaced with bone tissue.

Endochondral Ossification Endo=within Chondral=cartilage What type of bone is this? Long Short Flat Irregular Sesamoid

Intramembranous bone Intra=within What type of bone is this? Long Short Flat Irregular Sesamoid

Formation begins with…. Endochondral Long bones are initially formed from a cartilage model Intramembranous Flat bones are initially formed of connective tissue membranes .

Blood supply? Why?

Results in compact bone? Results in spongy bone?

Growth of Long Bones Study the picture and then finish the notes. Figure 6.8

Growth: Enlarging Your Bones Lengthwise growth of long bones occurs in cartilage structures called epiphyseal plates. Epiphyseal plates are four-layered structures found between the epiphysis and diaphysis of long bones. Epiphyseal plates are converted to bone following puberty, ending our ability to increase in height.

Is this person done growing? How do you know?

Increasing Bone Diameter. As your bones lengthen, they must also increase in diameter. They do this be increasing osteoblast activity in the periosteum. They must also increase the diameter of their medullary cavity. They do this by increasing osteoclast activity in the endosteum.

Remodeling: Keeping Your Bones New. Throughout life, we remodel bones to keep them new. Osteoclasts resorb bone matrix to make room for new matrix. Osteoprogenitor cells produce new osteoblasts Osteoblasts produce new bone matrix. Word bank: Osteoprogenitor, Osteoblast, Osteocyte, Osteoclasts

Remodeling Figure 6.10 Figure 6.9

Bone Disease: Osteoporosis Compare normal bone and osteoporosis. Collagen framework and deposited minerals are broken down faster than they are formed normally What happens to the strength of the bone during osteoporosis? The canals that connect the osteocytes become wider weakening the bone

Bone Disease: Sarcoma Bone cancer Osteosarcoma is the most common and occurs in long bones Chondrosarcoma occurs mainly in the pelvis, ribs and sternum

Osteochondroma What’s wrong with Curtis? Non-cancerous bone growth

Non-cancerous bone tumor After removal of a tumor on the femur, a 7 inch incision was made to insert stabilizing hardware.

Bone Disease: Osteomyelitis Infection of a bone, usually by bacteria Watch Amazing Medical Stories

Bone disease: Osteomalacia What do you notice in the X-ray? A loss of calcium and phosphorus, often as the result of vitamin D deficiency, can cause weak bones Known as rickets

Bone Fractures Depends on the direction and degree of force. Types -Simple- bone remains beneath the skin -Compound- bone projects above skin

What type is this?

Angular to bone axis Twisted Partial Right angle to bone axis Crushed

What’s wrong with Mitch Transverse fracture

Ryan Regeth What’s wrong? Broken clavicle at the acromion process

Zach Janczak What’s wrong? 4th metacarpal

Alyssa Woo Stress Fracture: -tiny cracks in a bone -caused by the repetitive application of force, often by overuse -common in track athletes

Ms. Cerletty What’s wrong? Patellar ACL autograft, screw protruding from tibia after 22 years

Michael Mathwick After surgery Before surgery

What’s wrong? Note the bloody area on the bone. This is where a piece of the femur is missing.

Allograft from a cadaver

Repaired bone

Bone Repair 1 hour Several days 1-2 weeks 2-3 months Soft, spongy bone is deposited on the callus, blood vessels heal and grow across the break New compact bone replaces the callus, completing the repair C. Blood leaking from the site of injury rapidly forms a clot D. Fibroblasts form a callus. The callus gradually bridges the gap between the broken bone ends, replacing the clot 1 hour Several days 1-2 weeks 2-3 months