Cartilage Flashcards
What is cartilage?
An avascular connective tissue that consists of an extensive extracellular matrix in which lie chondrocytes.
What produces and maintains the extracellular matrix in cartilage?
Chondrocytes
Why is there a large ratio of glycosaminoglycans to type II collagen in the cartilage matrix?
Permits ready diffusion of substances between the chondrocytes and the blood vessels that surround the cartilage
What assists the resilience of cartilage to the repeated application of pressure?
Large amount of hyaluronic acid in the extracellular matrix
What does the high density of negative charges on the GAGs do?
Attracts water, forming a hydrated gel
What does hyaluronic acid together with its attached proteoglycan monomers form?
A hyaluronate proteoglycan aggregate
What are the three types of cartilage?
Hyaline, Elastic and Fibrocartilage
What does the matrix of hyaline cartilage consist of?
Proteoglycans, hyaluronic acid and type II collagen
What does the matrix of elastic cartilage consist of?
Has a matrix like hyaline cartilage but with the addition of many elastic fibres and elastic lamellae
What does the matrix of fibrocartilage consist of?
Has a matrix like hyaline cartilage but with the addition of abundant type I collagen fibres
What is the cell type found in hyaline cartilage?
Chondrocytes
What are isogenous groups?
Small clusters of recently divided chondrocytes
When do the chondrocytes within the isogenous groups seperate?
As they lay down the extracellular matrix
In early fetal development, hyaline cartilage is the precursor model of the bones which develop via which type of ossification?
Endochondral ossification
As long bones develop, where does some hyaline cartilage remain?
At the articulating surface and also at the epiphyseal plate until growth ceases
Where is hyaline cartilage found in the body?
Articulating surfaces, rib cage, trachea, bronchi and larynx
What is the perichondrium?
Dense irregular connective tissue that covers the margin of hyaline cartilage
What does the perichondrium contain?
Many elongated, fibroblast-like cells which can develop into chondroblasts and thereafter into chondrocytes
What is appositional growth of cartilage?
Fibroblasts in the perichondrium give rise to flat, newly formed chondroblasts which secrete matrix components and round up to develop into chondrocytes, resulting in cartilage growth.
The process of appositional growth occurs when the cartilage model also grows in thickness due to the addition of more extracellular matrix on the peripheral cartilage surface, which is accompanied by new chondroblasts that develop from the perichondrium.
What is interstitial growth of cartilage?
The cartilage model will grow in length by continuous cell division of chondrocytes, which is accompanied by further secretion of extracellular matrix. The cells of the isogenous groups separate as they lay down further matrix.