Objective For Cartilage and bone part 1

Hyaline Cartilage: Contains type II collagen, proteoglycans, and multiadhesive glycoproteins.

Elastic Cartilage: Contains elastic fibers, elastic lamellae, and components of hyaline cartilage.

Fibrocartilage: Contains type I collagen and all components of hyaline cartilage.

Chondroblast: Immature cartilage cells that produce the cartilage extracellular matrix (ECM).

Chondrocyte: Mature cartilage cells within lacunae, responsible for maintaining the matrix.

Perichondrium: Dense irregular connective tissue surrounding cartilage (except articular cartilage); provides nutrients and new cartilage cells.

Hyaline Cartilage: Smooth, amorphous matrix, type II collagen, lacunae with chondrocytes, and a perichondrium (except in articular cartilage).

Elastic Cartilage: Dense network of branching elastic fibers, chondrocytes in lacunae, and perichondrium present.

Fibrocartilage: Combination of dense connective tissue and cartilage, with chondrocytes in rows or isogenous groups, and no perichondrium.

Hyaline Cartilage: Found in nasal septum, tracheal rings, costal cartilage, and articular surfaces → Provides smooth surfaces for joint movement and structural support.

Elastic Cartilage: Found in external ear (pinna), epiglottis, and Eustachian tube → Provides flexibility.

Fibrocartilage: Found in intervertebral discs, menisci, pubic symphysis, and tendinous insertions → Provides tensile strength and resistance to compression.

Chondroprogenitor mesenchymal cells aggregate into chondrogenic nodules.

SOX-9 transcription factor triggers differentiation into chondroblasts.

Chondroblasts secrete cartilage matrix and become chondrocytes.

Surrounding mesenchymal tissue forms the perichondrium.

Appositional Growth: New cartilage forms at the surface from perichondrium-derived chondroblasts.

Interstitial Growth: New cartilage forms within existing cartilage by chondrocyte division.

Calcium phosphate crystals deposit in the matrix.

Occurs in: Endochondral ossification during bone growth. Aging (common in tracheal cartilage). Articular cartilage areas near bone. Leads to chondrocyte death and replacement by bone tissue.

Extracellular matrix degrades.

Chondrocyte metabolism alters.

Glycosaminoglycan (GAG) content decreases.

Matrix metalloproteinase enzymes increase, leading to breakdown of proteoglycans and collagen.

Results in loss of cartilage, bone-on-bone contact, and joint pain.

Hyaline Cartilage: Type II collagen, proteoglycans, and multiadhesive glycoproteins; found in joints, nasal septum, trachea.

Elastic Cartilage: Type II collagen + elastic fibers; found in ear, epiglottis, Eustachian tube.

Fibrocartilage: Type I collagen + type II collagen; found in intervertebral discs, menisci, pubic symphysis.

Hyaline Cartilage:

Lacunae: Spaces containing chondrocytes. Chondrocytes: Cartilage cells within lacunae. Isogenous Groups: Clusters of chondrocytes from division. Extracellular Matrix: Composed of capsular, territorial, and interterritorial regions. Perichondrium: Present (except in articular cartilage). Elastic Cartilage:

Same features as hyaline cartilage but with elastic fibers. Fibrocartilage:

No perichondrium. Chondrocytes in rows or clusters. Type I collagen fibers in the matrix.