Cartilage Flashcards
Ground substance in cartilage? 4
Proteoglycans 40% of dry weight
Glycoproteins
Lipids
Water 80-90% of total weight
Chondroblast vacuoles contain?
Lipid and glycogen
Function of chrondroblasts?
Synthesise and destroy ECM
Contents of ECM?
Fibrillary component and ground substance
Avascular, a-neural
Surrounded by perichondrium (except hyaline cartilage - articular surface)
Functions of cartilage?
Embryo bone formation
Growth of long bones (metaphyseal cartilage)
Articular surface - reduce friction
Shock absorb - bear stress
Where is metaphysis
Between epiphysis and diaphysis (shaft)
Cells of cartilage?
Chondroblasts - located in perichondrium. Active nucleus. Vacuoles containing lipid + glycogen.
Chondrocytes - mature cell, lacunae, isogenous groups, deeper into cartilage more globular
Fibroblasts - outer layer of perichondrium
Cartilage ECM (fibres and ground substance)
Fibres: type 2 collagen(50% of dry weight)
Ground substance: proteoglycans, glycoproteins, lipids, water
Also type 1 collagen and elastic fibres (elastic cartilage)
Proteoglycan structure?
Core protein linked to many GAGs
Proteoglycan aggregates?
Hyaluronic acid central molecule.
Core proteins of proteoglycans attached via linker proteins
Perichrondrium contains? And extra facts?
Fibroblasts, Chondroblasts, Nerve, blood, lymphatic supply.
Not in articular cartilage
Req for cartilage healing
Is made of DCT
Perichondrium inner layer
Chondrogenic layer
Chondrocytes present
2 methods of cartilage growth?
Synthesised by?
What is synthesised?
Interstitial - only during development of tissue
Appositional
Mesenchymal cells -> Chondroblasts
Synthesise M of cartilage - proteoglycans, gags, chondronectin, collagen, elastic fibres
Appositional growth (3)
Perichondrium inner layer - differentiate - ecm components
New fibroblasts produced - maintain pop of perichondrium
After birth perichondrium not produced chondroblast
Interstitial growth? (3)
Partition formed between daughter cells
Chondrocytes within lacunae - mitosis + secrete ecm + move apart as secrete
Formation of joint cartilage?
Articular cartilage, no perichondrium, no appositional growth.
Only interstitial
Cartilage (inter)territorial matrix
Territorial matrix - darker stain - gags + proteoglycans
Stain for elastin fibres?
Stain for proteoglycans?
Weigert stain
PAS stain
Cartilage function and how? (3)
Bear mechanical stress - proteoglycans - bind to water - absorb compressive forces
No perm distortion - resist tensile forces
Collagen compression similar to iron
Cartilage classification. Hyaline and where found?
Type 2 collagen
Isogenous groups
Amorphous no fibre matrix
Bronchi, larynx, pharynx, articular surface, nose, trachea, ribs ventral ends, bone formation
Cartilage classification. Elastic and where found?
Elastin fibres - resist repeated bending. Use weigert stain.
Compared to hyaline - isogenous groups closer - fewer and smaller
Elastic fibres in all directiom
Pinna of ear, external ear, epiglottis, auditory tube
Cartilage classification. Fibrocartilage and where found
.
Both collagen type one and type 2.
White heterogenous appearance.
Intermediate between hyaline and dct.
Pubic symphysis, knee meniscus, intervertebral disk
Cartilage ageing (2)
Abnormal collagen fibres increase - unstable - destroyed - cavities form - asbestiform degeneration
Decrease in proteoglycans - decrease water - less efficient absorption of nutrients and hormones + effects resistance
Hyaline cartilage extra 3 points?
Supports respiratory system, forms fetal skeleton, glassy scare collagen fibres
