3 The Skeletal System Free Online FlashCards

What are the roles of osteoblasts, osteoclasts, and osteocytes?

Osteoblasts build bone matrix, osteoclasts break it down, and osteocytes help maintain it.

How do compact and spongy bone differ?

Compact bone is dense and strong, while spongy bone is a lighter network of bony struts with spaces that often contain red marrow.

What is the periosteum?

The periosteum is the thin outer membrane of bone; it carries blood vessels and nerves and provides attachment sites for tendons and ligaments.

What does articular cartilage do at joints?

Articular cartilage covers bone surfaces where they meet at joints, helping reduce friction and absorb impact.

What is intramembranous ossification?

Intramembranous ossification forms bone directly from embryonic connective tissue; it produces many skull bones and parts of the clavicles.

What happens during endochondral ossification?

Endochondral ossification replaces a cartilage model with bone and forms most bones, including the long bones of the limbs.

How does the epiphyseal plate lengthen a growing bone?

Cartilage at the epiphyseal plate is gradually replaced by bone, lengthening the bone as it grows.

What does the axial skeleton include?

The axial skeleton forms the body's central axis and contains 80 bones, including the skull, vertebral column, ribs, and sternum.

What makes up the appendicular skeleton?

The appendicular skeleton contains 126 bones: the limbs and the girdles that attach them to the axial skeleton.

What characterizes a synovial joint?

A synovial joint has a fluid-filled cavity between articulating bones. It is generally highly mobile, and synovial fluid lubricates its moving surfaces.

How do synarthroses, amphiarthroses, and diarthroses differ?

Synarthroses are immobile or nearly immobile, amphiarthroses are slightly movable, and diarthroses are freely movable.

How do elbow and shoulder joint shapes differ?

The elbow is a hinge joint, allowing bending and straightening; the shoulder and hip are ball-and-socket joints, allowing movement in several directions.