Cartilage Histology Flashcards
chondroblasts
cells that secrete cartilage matrix; have mitotic capabilities
chondrocytes
mature cartilage cells in lacunae; come from the chondroblasts; surrounded by and maintain matrix
what type of collagen is predominant in cartilage
type II
hyaline cartilage
- surrounded by what
- contains what type of collagen
- location
- perichondrium
- type II collagen
- articular cartilage, larynx, trachea, ribs, embryonic, development
elastic cartilage
- made of what
- surrounded by what
- contains what type of collagen
- location
- consists of hyaline cartilage plus elastic fibers
- surrounded by perichondrium
- type II collagen
- external ear, epiglottis, auditory tube
fibrocartilage
- made of what
- surrounded by what
- contains what type of collagen
- location
- combo of hyaline cartilage and dense regular CT
- NO perichondrium
- type I collagen and type II via hyaline cartilage
- intervertebral discs, pubic symphysis, TMJ
isogenous groups
- what are they
- where are they found
2 or 3 chondrocytes forming together in a group
- found in hyaline, elastic, and fibrocartilage
territorial matrix
darkly stained tissue in hyaline cartilage surrounding isogenous groups
- high in GAGs
- consists of type II collagen
interterritorial matrix
lightly stained tissue surrounding the darker stained territorial matrix
- consists of more collagen type II
- fewer proteoglycans
epiphyseal plate
hyaline based “growth plate”
perichondrium
- made of what
- surrounds what
- source for what
- other function
dense irregular connective tissue
- surrounds hyaline and elastic cartilage
- source of new cartilage cells
- nutrients diffuse through this
fibrous layer of perichondrium
outer layer that produces type I collagen and elastin
- has more of the vasculature
chondrogenic layer of perichondrium
inner layer that differentiates into chondroblasts and secretes type II collagen
function of fibrocartilage
withstands compression and shearing forces
appositional growth chondrogenesis
- what is it
- location
- process
“rings of a tree growth”; forms new cartilage on the surface of existing cartilage; increase in girth of cartilage
- occurs within inner layer of perichondrium
cells –> chondroblasts –> secrete type II collagen and ground substance
interstitial growth chondrogenesis
- what is it
- location
- features
less common
chondrocytes divide within the lacunae which creates new isogenous groups; increase in length of cartilage
- occurs within a cartilage mass in lacunae
- secrete more matrix
- avascular process
components of the cartilage matrix
type I collagen, type II collagen, elastin fibers, ground substance
cartilage repair
- limited capacity due to avascular nature
- facilitates healing of bone fracture
- ability is age dependent
repair cartilage
forms in cartilage repair when perichondrium is involved
- contains type I and II collagen
- can stimulate bone growth in some cases
articular capsule of synovial joints
outer fibrous layer made of dense regular connective tissue that surrounds and strengthens the joint
- contains extrinsic and intrinsic ligaments
difference between extrinsic and intrinsic ligaments in the articular capsule
extrinsic are separate from the capsule and intrinsic are part of the fibrous capsule
articular cartilage in synovial joints
- made of
- function
- vasculature?
- nourishment source
- hyaline cartilage
- reduces friction
- avascular, lacks nerve supply
- nourished by synovial fluid
synovial membrane (synovium) in synovial joints
- location
- function
- vasculature?
- produces what
- other features
- lines joint cavity except for articular cartilage
- lubricates articular cartilage
- vascular
- synovial fluid
- regenerative
- absorbs shock
Synoviocytes
make up the synovial membrane; play a crucial role in the pathogenesis of chronic inflammatory diseases
- two types:
type A macrophage-like synovial cells
type B fibroblast-like synovial cells
type A macrophage-like synovial cells in synovial joints
type of synoviocyte
- phagocytic, regulate inflammatory events, clear articular cavity of debris
- contain lysosomes
- 25% of cells lining synovium
type B fibroblast-like synovial cells in synovial joints
type of synoviocyte
- produce synovial fluid and hyaluronate
- lubricates and nourishes the articular cartilage
superficial zone of articular cartilage
- chondrocyte characteristics
- how do the collagen fibers run
- small and flattened chondrocytes parallel to the surface
- collagen fibers run parallel to the surface
intermediate zone of articular cartilage
- chondrocyte characteristics
- how do the chondrocytes occur
- how do the collagen fibers run
- slightly larger and round chondrocytes
- chondrocytes occur both alone and in isogenous groups
- collagen fibers take oblique course through matrix
deep zone of articular cartilage
- chondrocyte characteristics
- how are the chondrocytes arranged
- how do the collagen fibers run
- large chondrocytes
- chondrocytes form radial columns; stacks are oriented perpendicular to the articulating surface
- fibers follow orientation of chondrocyte columns
calcified zone of articular cartilage
- where is it
- how does it stain
- rests on underlying cortex of bone
- stains darker than other layers
Osteoarthritis
degenerative joint disease characterized by chronic joint pain, various degrees of joint deformity, and destruction of the articular cartilage
- commonly affects weight-bearing joints (knees, hips, lumbar vertebrae, hand and foot joints)
early stages of osteoarthritis
superficial layer of the articular cartilage is disrupted
late stages of osteoarthritis
destruction of the cartilage extends to the bone, where the exposed subchondral bone becomes a new articular surface
- progressive reduction of mobility and increased pain
ground substance
amorphous gel material that fills the spaces between fibers and cells in the ECM
- composed of proteoglycans
