Cartilage and Bone Tissue Flashcards
What are the functions of cartilage?
Development and growth of long bones
Supporting soft tissues
Providing a smooth, gliding surface at joints
Giving flexibility
What are the characteristics of cartilage?
-It is a connective tissue, extracellular fibers embedded in a matrix which has cells localized in small cavities
-Avascular, no lymphatics, no nerves
-Nourished by diffusion through the matrix
-Damaged cartilage does not repair itself
What are the three main components of cartilage?
Specialized cells, extracellular matrix, fibres
What is perichondrium?
Outer covering of hyaline and elastic cartilage
What is extracellular matrix?
Molecules that provide biochemical and structural support to the cells
What are the two layers of perichondrium?
Outer fibrous layer with fibroblasts
Inner cellular layer with chondroblasts
What are the functions of perichondrium?
Retains capacity to form new cartilage - initiates appositional growth
Provides nutrition to cartilage
What are two ways cartilages grow?
Appositional or exogenous growth
Interstitial or endogenous growth
What is appositional growth?
Chrondroblasts from the inner cellular layer of the perichondrium differentiate into chondrocytes and produce matrix.
It’s growth from outside the cartilage. Cartilage increases in width. Occurs in mature cartilages.
What is interstitial growth?
Chondrocytes within the cartilage divide by mitosis and secrete new matrix. Growth from within the cartilage. Cartilage increases in length. Occurs in young cartilage and epiphyseal plates.
How does the growth of cartilage take place?
Mesenchymal stems cells round up and retract extensions to form chondroblasts. Chondroblasts divide through mitosis and form centers of chondrification. They start to produce matrix and collagen fibers. Chondroblasts separate from one another and differentiate into chondrocytes. Chondrocytes are immobile and trapped within matrix. Chondrocytes divide through mitosis. Daughter cells produce additional matrix and move apart (interstitial growth). Superficial mesenchymal develops into the perichondrium.
What does the extracellular matrix consist of?
Fibers- collagen I, collagen II, elastic
Ground substances- hydrated gel of GAGs, proteoglycans and glycoproteingv
