chapter 5

Long bones

Bones that are longer than they are wide, found in the arms and legs.

Short bones

Bones that are fairly equal in width and length, found mostly in the wrists and ankles.

Flat bones

Thinner bones that can be flat or curved, such as the skull, ribs, and sternum.

Irregular bones

Bones that are odd in shape, like parts of a jigsaw puzzle, including the hip bone and vertebrae.

Periosteum

A tough and fibrous connective tissue that covers bones, containing blood vessels, lymph vessels, and nerves.

Epiphysis

Both ends of a long bone, which increase in size.

Diaphysis

The hollow region between the two epiphyses of a long bone.

Compact bone

Dense, hard tissue that composes the shafts of long bones and the outer layer of other bone types.

Osteons

Microscopic, cylindrical shaped units that compose compact bone, also known as haversian systems.

Spongy bone

Also known as cancellous bone, arranged in trabeculae with irregular holes for lighter weight and space for red bone marrow.'

Ossification

The process of bone formation in the body.

Osteoprogenitor cells

Non-specialized cells found in the periosteum, endosteum, and central canal of compact bones, capable of turning into other types of cells.

Osteoblasts

Cells that form bones and arise from osteoprogenitor cells by secreting a matrix that gives bone its structure.

Osteocytes

Mature bone cells derived from osteoblasts that are surrounded by bone matrix.

Osteoclasts

Cells that tear down bone material and help move calcium and phosphate into the blood.

Intramembranous ossification

Bone development occurring between two sheets of fibrous connective tissue.

Endochondral ossification

The process where shaped cartilage is replaced by bone.

Epiphyseal plate

A thin band of cartilage that allows long bones to grow in length.

Cartilage

A type of dense connective tissue that provides flexible support and is found in joints.

Articular cartilage

Cartilage located at the ends of bones, functioning as a shock absorber.

Synovial fluid

A lubricant secreted by a bursa to reduce friction in joints.

Ligaments

Tough connective tissues that connect bones to bones at joints.

Tendons

Cord-like structures that attach muscles to bones.

Pivot joint

A joint allowing turnstile movement, found in the neck and forearm.

Ball and socket joint

A joint that allows all forms of movement, found in the hip and shoulder.

Hinge joint

A joint allowing opening and closing movement, such as in knees and elbows.

Osteoporosis

A condition where bone mass decreases with age, making bones weaker and more prone to fractures.