Skeletal System

Osteology

the study of bones and the skeletal system.

Bone matrix

The extracellular framework of bone tissue, composed primarily of collagen fibers and minerals. It provides strength and structure, supporting bone cells.

Osteoblast

A type of cell responsible for bone formation by producing the bone matrix and facilitating mineralization.

Osteoclast

A type of bone cell responsible for the resorption and breakdown of bone tissue, playing a crucial role in bone remodeling and calcium homeostasis.

Osteocyte

A mature bone cell derived from an osteoblast, it helps maintain bone tissue and communicate with other bone cells.

Lacuna

A small cavity within the bone matrix that houses osteocytes, facilitating communication and nutrient exchange.

Canaliculi

Small channels that connect lacunae and allow for communication between osteocytes in bone.

Osteon

The basic structural unit of compact bone, consisting of a central canal surrounded by concentric lamellae and osteocytes in lacunae.

Central canal

The central canal is a hollow structure within an osteon that contains blood vessels and nerves, providing essential nutrients and signals to bone cells.

Circumferential lamellae

Layers of bone that encircle the outer and inner surfaces of compact bone, helping to provide structural integrity and strength.

Spongy bone

A type of bone tissue that is light and porous, found largely at the ends of long bones and in the interior of others. It consists of trabeculae that house red bone marrow and contribute to the overall strength and flexibility of bones.

Compact bone

A dense and strong type of bone tissue that forms the outer layer of bones, providing protection and support. It is organized into cylindrical structures called osteons.

Trabeculae

The small rod-like or plate-like structures found in spongy bone, providing support and housing bone marrow. They create a network that enhances flexibility and reduces the weight of bones.

Red bone marrow

The flexible tissue found in the cavities of bones that produces blood cells, including red blood cells, white blood cells, and platelets. It is essential for hematopoiesis and is located primarily within the spongy bone.

Yellow bone marrow

A type of bone marrow that is primarily composed of fat cells and serves as an energy reserve. It is found in the medullary cavities of long bones and can convert to red bone marrow in times of severe need.

Endosteum

The thin membrane lining the inner surfaces of bones, including the medullary cavity and trabecular cavities. It plays a crucial role in bone growth and repair.

Periosteum

A dense layer of vascular connective tissue that covers the outer surface of bones, except at the surfaces of the joints. It plays a key role in the growth, repair, and nutrition of bones.

Medullary cavity

The central cavity of a long bone, filled with bone marrow and surrounded by a thick layer of compact bone. It is essential for the production of blood cells and the storage of fat.

Intramembranous ossification

The process by which bone develops directly from mesenchyme tissue without a cartilage intermediate, typically seen in flat bones like the skull.

Endochondral ossification

A process of bone development in which cartilage is replaced by bone tissue, critical for the formation of long bones during fetal development and growth.