2.2 Bone Cells & Tissue

Canaliculi (singular = canaliculus)

Channels within the bone matrix that house one of an osteocyte's many cytoplasmic extensions, used to communicate and receive nutrients

Central canal (Haversian canal)

Longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels

Chondrocytes

Cells of the cartilage

Lacunae (singular = lacuna)

Small spaces in bone or cartilage tissue that cells occupy

Matrix

Extracellular material produced by the cells embedded in it; contains ground substance and fibers

Osseous tissue

Bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton

Osteocyte

Primary cell in mature bone; responsible for maintaining the matrix

Osteon (Haversian system)

Basic structural unit of compact bone; made of concentric layers of calcified matrix

Perforating canal (Volkmann's canal)

Channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum

Lamellae

Concentric circles or layers of calcified bone matrix surrounding the central canal; primary site of lacunae

Lacunae

Tiny, fluid-filled cavities within the hard bone matrix that contain mature bone cells (osteocytes)

Osteocytes

Mature bone cells residing inside lacunae that maintain the health, nutrient exchange, and structural integrity of the surrounding bone matrix

Canaliculi

Microscopic, branching canals radiating outward from the central canal to the lamellae and lacunae, forming a transport network that connects bone cells to a nutrient/blood supply

Osteoblasts

Bone-building cells that actively synthesize and secrete the organic components of the bone matrix

Osteoclasts

Large, multinucleate cells responsible for bone resorption; break down bone tissue to release calcium and assist in remodeling

Red bone marrow

Connective tissue found within spongy bone spaces that is responsible for hematopoiesis (production of blood cells)

Yellow bone marrow

Adipose-rich tissue located within the central medullary cavity of long bones; functions primarily as a site for fat and energy storage

Epiphysis

The expanded end portion of a long bone, typically composed of spongy bone covered by a thin layer of compact bone

Spongy bone

Lightweight type of bone tissue consisting of a latticework of thin bony plates (trabeculae); found predominantly in the epiphyses and internal regions of bones

Periosteum

Dense, fibrous membrane covering the outer surface of bones; serves as an attachment point for tendons and contains blood vessels and bone-forming cells