May22 M2-Histo 1 Flashcards
cartilage def
specialized CT where ECM is firm
cartilate type in trachea
hyaline cartilage
hyaline cartilage charact + surrounded by what
- homogenous ECM, looks transparent
- don’t see collagen fibers
- surrounded by perichondrium (border) on both sides
cells in hyaline cartilage
- chondrocytes. found in clusters, forming groups called isogenous groups.
- isogenous groups are in spaces called lacunae
function of cartilage
provide support to adjacent tissues (in trachea, keeps trachea open, easier air circulation)
cartilage important charact
no blood vessels
3 types of cartilage and how make diff types
- hyaline
- elastic
- fibrocartilage
- made by variations in the constituents: CT fibers of the ECM and proteoglycans*
main components of ECM in cartilage
- fibers (type 2 collagen in elastic and hyaline + some other types of collagen)
- amorphous ground substance (proteoglycans and glycoproteins)
main fiber in hyaline and elastic cartilage ECM
type 2 collagen
main proteoglycan in cartilage ECM
chondroitin sulfate (SO4)
main glycoprotein in cartilage ECM
chondronectin
type 1 collagen is found where in the body
- loose and dense CT
- fibrocartilage
- bone
component specific to elastic cartilage
elastic fibers
structure of proteoglycans and what proteoglycans are bound to
- protein core (long linear protein) with lateral chondroitin sulfate side chains
- the core protein binds to a link protein, which binds to hyaluronic acid (perpendicular to protein core)
- so chondroitin sulfate is the name of a proteoglycan which has chondroitin sulfate side chains on a protein core*
chondroitin sulfate vs chondronectin composition in sugars and proteins
chondronectin = 90% proteins 10% sugars
chondroitin sulfate = 50% protein 50% sugars
most important proteoglycan in hyaline cartilage ECM and why
chondroitin sulfate. bound to water so large amount of water acting as cushions in the joint
how to diff between hyaline and elastic cartilage
Verhoeff Hematoxylin stain. stain elastic fibers
only way to differentiate
what elastic fibers allow in elastic cartilage
- subject to change and stretchy
- give elasticity to cartilage
disposition of elastic fibers in elastic cartilage
- form network around lacunae
- bit at the level of the perichondrium also
typical cell type of cartilage mature and immature form
- chondroblast (immature)
- chondrocyte (mature)
function of chondrocytes (in isogenous groups contained in lacunae)
secrete the ECM of the cartilage (type 2 collagen, hyaluronic acid, proteoglycans, glycoproteins, +/- elastic fibers
2 layers of perichondrium and charact
- fibrous perichondrium (outer) = collagen fibers in same directions + inactive fibrocytes, elongated cells
- chondrogenic perichondrium = clear cytoplasm, central nucleus, active site of chondroblast division and chondrocytes formation
chondroblast location in cartilage (hyaline for ex) and what they do
in chondrogenic perichondrium, make the chondrocytes
2 types of cell growth in cartilage (hyaline cartilage) and description
- appositional growth at the chondrogenic perichondrium (chondroblasts making chondrocytes pushing them in matrix)
- interstitial growth inside lacunae (division of chondrocytes)
most important type of growth in cartilage (hyaline and elastic) and why
appositional. if there’s a tear, it will repair cartilage. articular surfaces don’t have perichondrium so no repair
* interstitial growth doesn’t play a role in repair*
where cartilage persists in bone + type of cartilage
at articular surface
HYALINE cartilage on articular surfaces
cartilage at articular surface characteristics
- smooth surface facing synovial cavity bc NO PERICHONDRIUM (was only present when cartilage being made)
- isogenic groups organized in parallel lines