Structure of a typical long bone

What is the general structure for all long bones

A shaft, bone ends, and membranes

What is the diaphysis

The shaft of a long bone

What does the diaphysis consist of

A relatively thick collar of compact bone that surrounds the medullary / marrow cavity

Does the medullary cavity contain bone tissue

No

What is in the medullary cavity

Yellow bone marrow (fat) in adults; often called the yellow marrow cavity

is there spongy bone in the diaphysis

yes, there is often a thin layer between the compact bone and medullary cavity

What is the epiphysis

The ends of long bones

How is the epiphysis laid out

It has an outer layer of compact bone, which forms the epiphyseal exterior, and an inner layer of spongy bone

What covers the epiphyseal

Hyaline cartilage covers the joint surfaces of each epiphyseal

What does the hyaline cartilage at the joint surfaces do

Cushions the opposing bone ends during movement and absorbs stress

What is between the diaphysis and epiphysis of an adult long bone

epiphyseal line

What is the epiphyseal line

The growth plate; it is closed in adult bones. In growing bones, it is a disc of hyaline cartilage that allows for bones to lengthen.

What is the metaphysis

The flared portion of the bone where the epiphysis and diaphysis meet; typically on the epiphyseal plate or line

What are the membranes of long bone

The periosteum and endosteum

What is the periosteum

A white, double-layered membrane that covers the external surface of long bones except for the joints

What are the layers of the periosteum

Outer fibrous layer and inner osteogenetic layer

What is in the osteopenia layer of the periosteum

Osteoprogenitor cells, osteoclasts, and osteoblasts

What are osteoprogenitor cells

Mesenchymal stem cells that divide to produce bone cells (osteoblasts -> osteocytes)

is the periosteum in long bones vascular

Yes, it has a rich supply of nerves and blood vessels

Why do broken bones hurt and bleed

The periosteum has a rich supply of nerve cells and blood vessels

What are perforating fibers

Collagen fibers of the periosteum that extend into the bony matrix and secure the periosteum to the bone

What can anchor to the periosteum and how does this change its composition

Tendons and ligaments can anchor to the periosteum; the perforating fibers are extra dense in these areas

What is the endosteum in long bones

The delicate CT membrane that covers the internal portion of the bone surfaces

What cells are present in the endosteum

osteoblasts, osteoprogenitor cells, and osteoclasts; the same cells as the inner later of the periosteum

What does the endosteum cover/line in the long bones

It lines the canals and covers the trabeculae

What are the main vessels that serve the diaphysis of long bones

The nutrient artery and a nutrient vein

Where do the nutrient artery and vein run through in the wall of the diaphysis

The nutrient foramen

What does the nutrient artery supply

it runs inward to supply bone marrow and spongy bone; branches extend outward to supply the compact bone

How do the epiphysis get nutrients

Epiphyseal arteries and veins serve each epiphysis in the same way