Flashcards: Skeletal System Overview & Long Bone Anatomy

What are the 5 main functions of the skeletal system?

Support, protection, movement, mineral storage, blood cell formation.

What are the two divisions of the skeleton and how many bones are in each?

Axial (80 bones: skull, vertebral column, rib cage) and Appendicular (126 bones: limbs and girdles).

What is the total number of bones in an adult skeleton?

206.

What are the two types of bone tissue?

Compact bone (dense outer shell) and spongy/cancellous bone (porous, inner, honeycomb-like).

What are the 5 bone shape classifications?

Long (femur), short (carpals), flat (skull bones), irregular (vertebrae), sesamoid (patella).

What is the diaphysis?

The long shaft of a long bone, made of thick compact bone around a hollow center.

What is the medullary cavity and what does it contain in adults?

The hollow space inside the diaphysis; contains yellow marrow (fat storage) in adults.

What is the epiphysis?

The knobby end(s) of a long bone, made mostly of spongy bone with a thin compact bone shell.

What is the metaphysis?

The region between diaphysis and epiphysis where bone growth occurs.

What is the epiphyseal plate and what does it become after growth stops?

A layer of cartilage where bones lengthen; becomes the epiphyseal line once ossified.

What is articular cartilage?

Hyaline cartilage capping the epiphysis at joints, reducing friction/absorbing shock; it has NO periosteum covering it.

What is the periosteum and what does it cover?

A membrane covering the outside of the diaphysis (not joint surfaces); contains blood vessels, nerves, osteoblasts; anchors tendons/ligaments.

What is the endosteum and where is it found?

A thin membrane lining the inside surfaces of bone — the medullary cavity and spongy bone spaces.