PHYL 141: Osseous Tissue and Cartilage

Vocabulary practice flashcards covering supportive connective tissues, including cartilage types, bone cell lineages, matrix composition, and remodeling.

Connective Tissue Proper

A category of connective tissue that includes loose connective tissue and dense connective tissue.

Supportive Connective Tissue

A class of connective tissue comprising bone and cartilage that provides physical protection and structural support for the body.

Fluid Connective Tissue

A category of connective tissue with a liquid ground substance, consisting of blood and lymph.

Chondrocytes

Mature cartilage cells that reside in lacunae and maintain the extracellular matrix of cartilage.

Extracellular Matrix (ECM)

The non-cellular component of a tissue formed by extracellular protein fibers mixed with a fluid-like ground substance.

Glycosaminoglycans (GAGs)

Polymers composed of multiple repeating disaccharides (such as chondroitin sulfate and hyaluronic acid) that attract and recruit water for shock absorption.

Proteoglycans

Molecules found in the cartilage ground substance that thicken water to aid in shock absorption.

Perichondrium

A layer of dense irregular connective tissue that envelops the outer boundary of cartilage tissue.

Lacunae

Small pockets or spaces within the extracellular matrix where cells such as chondrocytes and osteocytes reside.

Interstitial Growth

A mode of cartilage growth from within, where a chondrocyte divides inside a lacuna and daughter cells produce new matrix that pushes them apart.

Hyaline Cartilage

The most common cartilage type, possessing short collagen fibers and a smooth, stiff, and flexible matrix; reduces friction between bone surfaces in synovial joints, ribs, larynx, trachea, bronchi, and nasal septum.

Fibrocartilage

A dense, tough cartilage with thick bundles of collagen fibers that resists compression and limits bone-to-bone contact in intervertebral discs, pubic symphysis, and knee menisci.

Elastic Cartilage

A flexible, resilient cartilage whose primary protein is elastin rather than collagen; recoils back to its original shape and is found in the auricle of the external ear, epiglottis, and auditory canal.

Osseous Tissue

Bone tissue; a specialized supportive connective tissue consisting of specialized cells and an extracellular matrix made of calcium salts covering collagen.

Osteology

The scientific study of bones and osseous structures.

Osteogenic Cells

Bone stem cells that divide and differentiate into osteoblasts.

Osteoblasts

Bone-building cells that synthesize and secrete the organic collagen matrix (osteoid) and facilitate the deposition of calcium salts.

Osteocytes

Mature, non-dividing bone cells located in lacunae that maintain bone matrix and initiate bone remodeling.

Osteoclasts

Large, multinucleated bone-resorbing cells derived from fused macrophages that dissolve and clear away bone matrix by secreting hydrochloric acid ($\text{HCl}$).

Osteoid

The unmineralized, jelly-like collagen matrix produced by osteoblasts prior to the incorporation of calcium salts.

Bone Alkaline Phosphatase (BAP)

An enzyme that catalyzes the mineralization reaction during bone formation.

Bone Remodeling

The continuous cyclical process of resorbing old or damaged bone tissue and replacing it with new osseous matrix.

Bone Matrix Composition

The osseous matrix comprising approximately $33\%$ organic compounds (mainly collagen) and $67\%$ inorganic mineral salts (primarily calcium and phosphate).

Fibroblasts

The most abundant cell type in connective tissue proper that secretes protein fibers (collagen, elastin, and reticular fibers) to build the extracellular matrix.

Fibrocytes

Mature, less active connective tissue cells that monitor and maintain preexisting extracellular matrix with lower rates of protein secretion.

Macrophages

Phagocytic cells that engulf debris and foreign particles; in bone physiology, multiple macrophages fuse together to form multinucleated osteoclasts.