Cartilage Biology Flashcards

Flashcards about cartilage structure, function, and development based on lecture notes.

Functions of Cartilage

Resists compression, provides resilience, provides support, and provides flexibility.

Articular cartilage

Avascular and aneural.

Hyaline cartilage locations

Nose, bronchi, ventral end of ribs, articular cartilage, trachea and in the embryonic skeleton

ECM compartments in hyaline cartilage

Pericellular, territorial, and inter-territorial.

Hyaline cartilage

It is surrounded by perichondrium, except for articular cartilage.

Articular cartilage zones

Superficial, middle, and deep zones.

Wet weight of cartilage

Water, collagen, and proteoglycans.

Dry weight of cartilage

Type II collagen and aggrecan.

Function of proteoglycans

Resist compressive forces.

Collagen types

Collagen I-XV.

Main collagen in cartilage

Collagen type II.

Superficial zone characteristics

Low cellularity, high proteoglycan content, and collagen I > II.

Mid zone characteristics

High cellularity and low proteoglycan content.

Deep zone characteristics

Mid/Low cellularity, reduced proteoglycan content and Collagen II.

Perichondrium layers

Fibrous (outer) and chondrogenic (inner).

Fibrous layer of perichondrium

Dense, irregular connective tissue.

Fibrocartilage

Additional resistance to tension, type-I collagen in bundles, less proteoglycan and no perichondrium

Fibrocartilage location

In IV disc, tendon, ligament attachment sites, menisci

Elastic cartilage

Greater toughness in bending, less plastic more elastic and large quantities of elastin.

Elastic cartilage location

Larynx, ear, Eustachian tube, epiglottis

Master regulator of chondrogenesis

Sox-9.

Chondrogenesis

A process used for establishing chondrogenic centers.

Stages of chondrogenesis

Condensation, cartilage matrix synthesis, and chondron formation.

Synovial joint development

Cell condensations, interzone, and cavitation.

Articular cartilage

ECM protects, permanent vs. transient, unstable phenotype / matrix removal, young vs. old, calcified cartilage / bone crosstalk.

Epiphyseal growth plate

Cartilage being replaced by bone and a template for bone formation.

Chondrocyte lineage in growth plate

Resting, proliferation, maturation, hypertrophy, and death.

Endochondral ossification stages

Mesenchymal condensation, chondroprogenitor proliferation, chondrogenesis and terminal differentiation, vascular invasion and cartilage matrix calcification, and ossification.

Endocrine regulation of growth plate cartilage

Differentiation, cartilage transitions and local regulation of growth plate cartilage.

Osteoarthritis

Degradation & mineralisation, greater subchondral thickness and osteophyte formation

Resting zone markers

Sox9, Col2a1, and aggrecan.

Hypertrophic zone markers

Runx2, Col10a1, MMP13 ALP and VEGF.

SOX9

Sox9 is required to keep growth plates open and to maintain articular cartilage integrity

Joints

Articulation between bony elements

Cartilage Nutrition

Nutrition mostly from synovial fluid and some from sub-chondral bone