Cartilage Flashcards
Is cartilage vascular or avascular?
Avascular
What is the name of the cells which lie within cartilage?
Chondrocytes
What do chondrocytes produce and maintain?
Extracellular matrix
What permits the ready diffusion of substances between the chondrocytes and the blood vessels surrounding the cartilage?
The large ratio of GAGs to type II collagen in the cartilage matrix
What are the properties of the extracellular matrix?
Solid and firm, but rather pliable and therefore resilient to the repeated application of pressure
What makes the extracellular matrix resilient to repeated application of pressure?
Large amounts of hyaluronic acid in the matrix.
Discuss the proteoglycan structure in cartilage ground substance
The proteoglycan monomer consists of a core protein to which approximately 100 glycosaminoglycan (GAG) units are joined. Hyaluronic acid molecules form linear aggregates, each with many proteoglycan monomers interwoven with a network of collagen fibrils
Why is cartilage ground substance a hydrated gel?
The high density of negative charges on GAGs attracts water
What are the 3 types of cartilage?
Hyaline, elastic, fibrocartilage
What is the composition of hyaline cartilage
A matrix containing proteoglycans, hyaluronic acid and type II collagen. The hyaluronate proteoglycan aggregates are bound to the fine collagen matrix fibres.
What is the composition of elastic cartilage?
A matrix like that of hyaline cartilage (containing proteoglycans, hyaluronic acid and type II collagen. The hyaluronate proteoglycan aggregates are bound to the fine collagen matrix fibres) but with the
addition of many elastic fibres and elastic lamellae.
What is the composition of fibrocartilage?
Matrix material like hyaline cartilage (containing proteoglycans, hyaluronic acid and type II collagen. The hyaluronate proteoglycan aggregates are bound to the fine collagen matrix fibres) but with abundant type 1 collagen fibres
What cell types are present in hyaline cartilage?
Chondrocytes only
Are chondrocytes present singly?
Yes’m or if recently divided, as small clusters called isogenous groups
When do chondrocytes separate?
The chondrocytes within the isogenous groups separate as they elaborate (lay down) extracellular matrix.
What is hyaline cartilage the precursor for in early fetal development?
Bones which develop by endochondral ossification
Where does hyaline cartilage remain in long bones?
As long bones develop some hyaline cartilage remains at the articulating surface, (and also at the epiphyseal plate until growth ceases).
Where is hyaline cartilage situated?
Hyaline caritlage is sited at articulating surfaces, in parts of the rib cage, nose, and in the trachea, bronchi and larynx.
What is perichondrium and what is its composition?
It covers the margin of hyaline cartilage. It contains many elongate, fibroblast-like cells which can develop into chondroblasts and thereafter into chondrocytes. It is a dense connective tissue.
What is a appositional growth?
The growth from the periphery. The fibroblast-like cells of the perichondrium give rise to flat, newly formed chondroblasts, which secrete matrix components and round up to develop into chondrocytes. (See lecture)
What is interstitial growth?
In addition, chondrocytes deeper in the cartilage may divide and give rise to growth. This is called interstitial growth.
The resultant cells separate as they lay down further matrix.