Cartilage Histology Flashcards
What does cartilage not have
Nerve supply, lymphatics, it is avascular
What is the function of cartilage
Provides support Withstands deformation Shock absorber Permit/reduces friction at joints Model for bone growth Fracture repair
What do chondroblasts do?
Secrete cartilage matrix
They have mitotic abilities
What do chondrocytes do?
They are mature cartilage cells found in lacunae
They are surrounded by and maintain the matrix
What is cartilage predominantly made of?
Type 2 collagen but fibrocartilage and outer perichondrium contain type 1
The ground substance of cartilage matrix is made of
Hyaluronic acid
Chondroitin sulfate
Keratin sulfate
Aggrecan
Hyaline cartilage is surrounded by what
Perichondrium
What kind of collagen is in hyaline cartilage
Type 2
Where is hyaline cartilage found
Articular cartilage, nasal septum, larynx, trachea, bronchi, embryonic development, ribs
What is elastic cartilage made of
Type 2 collagen
What surrounds elastic cartilage?
Perichondrium
Where is elastic cartilage found?
External ear, epiglottis, auditory tube
What is fibrocartilage like?
Hyaline cartilage and dense regular cartilage
What surrounds fibrocartilage
(Lacks perichondrium)
What is the primary type of collagen in fibrocartilage
Type 1
Where is fibrocartilage found?
Intervertebral discs, pubic symphysis, TMJ
What is hyaline cartilage made of
It is gel-like and amorphous but heterogenous
What makes articular cartilage different from hyaline cartilage
Articular lacks a perichondrium
What are the growth plates made of
Hyaline cartilage
What is the territorial matrix?
Moderately staining
Consists of randomly arranged type 2 collagen
Lots of proteoglycans
What is the interterritorial membrane
Surrounds the territorial matrix
Stains less intensely and has more collagen 2 and fewer proteoglycans
What is the outer layer of the perichondrium like?
It is the outer fibrous layer
Contains fibroblasts
Produces type 1 collagen and elastin
Transitional zone between cartilage and surrounding CT
What is the inner chondrogenic layer
It is the inner layer of the perichondrium that differentiates into chondroblasts that secrete type 2 collagen
What is elastic cartillage
It is similar to hyaline cartilage has elastic fibers within matrix
Surrounded by a perichondrium
Retains shape
Fibrocartilage is made of what
Type 1 and 2 collagen
How are chondrocytes arranged in fibrocartilage
They are arranged in columns to deal with functional stress
Where is fibrocartilage found?
Meniscus, intervertebral space, pubic symphysis
What are some unique properties about fibrocartilage
It lacks a perichondrium and it is opaque
What are the two types of cartilage growth
Appositional and interstitial
Where does appositional and interstitial growth take place?
A-forms new cartilage on surface of pre-existing cartilage
I-takes place within cartilage mass itself
Where does appositional and interstitial growth take place?
A-within inner layer of the perichondrium
I-chrondrocytes divide within lacunae, creating isogenous groups
What causes appositional and interstitial growth to take place?
A-chondrogenic cells produce collagen 1
I-new chondrocytes secrete more matrix, which increases overall mass of cartilage
How do appositional and interstitial growth take place
A-after growth is initiated, cells become chondroblasts and secrete collagen 2 and ground substances
I-overall growth due to secretion of new matrix and is limited by avascular nature
Describe cartilage repair
Formation of repair cartilage (intermediate of hyaline and fibrous cartilage (contains type 1 and 2 cartilage))
Cartilage is also replaced by dense connective tissue or bone
The more mobile a joint is _____________
The less stabile it is
What the gradations of joint based on movement
Synarthroses - little to no movement
Amphiarthroses - slightly movable
Diarthroses - freely moving (synovial joints)
What are type A macrophage like synovial cells
They are phagocytic
Contain lysosomes to clear articular cavity of debris
Make up 25% of cells lining the synovium
Regulate inflammatory events
What are type b fibroblasts
They produce synovial fluid (plasma filtrate)
Produce hyaluronate that combines with synovial fluid
Lubricates and nourishes the articular cartilage
What are the layers of articular cartilage
Tangental, transitional, radial, calcified cartilage
What is the tangental layer like?
Small chondracytes
Superficial layer devoid of cells
Collagen fibers run parallel to surface
What is the transitional layer
Slightly larger and rounder chondrocytes than the tangental, occur both alone and in isogenous groups, collagen fibers are on the diagonal, this is the largest layer
What is the radial layer?
Large chondrocytes that form radial columns, stacks are perpendicular to surface, collagen fibers follow the arrangement
What is calcified cartilage
Rests on underlying cortex of bone, matrix of calcified cartilage stains darker and allows blending with bone
What are the signs and symptoms of osteoarthritis?
Pain, tenderness, limited ROM, swelling, joint deformity
All due to the level of break down of cartilage
