Cartilage Flashcards
What are hyaline cartilage derived from?
Mesenchymal cells
What are the cells within hyaline cartilage?
Chondroblasts & Chondrocytes
What are in the extracellular matrix of hyaline cartilage?
Type 2 collagen fibers
GAGs- hyalauronic acid and glycoproteins
How does hyaline cartilage grow?
Appositional & interstitial growth
How does hyaline cartilage degenerate?
Doesn’t really degenerate
Describe the calcification of hyaline cartilage
Calcifies- bone formation & aging
What is the function of hyaline cartilage?
- supportive
- cushioning
- shock absorber
- growth plate
- model for bone formations
Describe the histology of the hyaline cartilage
Matrix has a “glassy” appearance because fibers and ground substance has the same refractive index
- ECM correlates to function!
- collagen
- sulfates groups
What are the locations of hyaline cartilage?
- Nose (cartilaginous portion)
- Tracheal and bronchial rings
- Laryngeal cartilages
- Costal cartilages
- Articular surfaces of long bones
- Epiphyseal growth plate
- Fetal skeleton
What is appositional growth?
Occurs from chondrogenic cells in the perichondrium differentiating into chondroblasts, forming a new layer of cartilage around the periphery of the existing cartilage
-This increases the width or thickness of the cartilage
What is interstitial growth?
Occurs only in young cartilage from cell divisions within the cartilage
-This increases the length of the cartilage
List in order of most influential first, what is the most influential hormones for growth?
- Growth hormone
- Thyroxine
- Testosterone
- Hydroxycortisone
- Estradiol
Summarize regeneration 9f hyaline cartilage
Hyaline cartilage regenerates very poorly and often the perichondrium forms scar tissue
When dies hyaline cartilage calcify?
In old age hyaline cartilages can get calcified
Describe Articular cartilage
A type of hyaline cartilage found at Articular surfaces
-does not have perichondrium
It is in contact with Articular surface of bone on opposite side
- Remnant of original cartilage template of developing bone
- Persists throughout adult life
What are the various regions of Articular cartilages?
- Trans genital layer
- Transitional layer
- Radial layer
- Calcified layer
What are elastic cartilage derived from?
Mesenchymal cells
What are the cells of elastic cartilage?
Chondroblasts and Chondrocytes
What is in the Extracellular matrix of elastic cartilage?
- type 2 collagen fibers and elastic fibers
- GAGs and glycoproteins, multi-adhesive glycoproteins
What kind of growth does elastic cartilage?
Appositional & interstitial growth
Does elastic cartilage degenerate
Doesn’t readily degenerate
Does elastic cartilage calcify?
Never calcify
What is the function of elastic cartilage?
Support with flexibility
What are the locations of elastic cartilage?
- Pinna of the ear
- external acoustic meatus
- Eustachian tube
- epiglottis
Is often found with hyaline cartilage
Is perichondrium present in elastic cartilage?
Yes
Contrast degeneration of elastic and hyaline cartilage
Does not degenerate as readily as hyaline cartilage
Where is elastic cartilage found functionally?
- located where support with flexibility is required
- matrix is identical to that of hyaline cartilage, except it also contains a network of elastic fibers that impart to it a yellowish color on visualization of the gross specimen
What are fibrocartilage derived from?
Mesenchymal cells
What are cells of the fibrocartilage?
Fibroblasts transform to Chondrocytes under stress
What is in the extracellular matrix of fibrocartilage ?
- produced by Chondrocytes and fibroblasts
- predominantly type 1 collagen fibers
- also contains type 2 collagen fibers
- GAGs- predominantly chondroitin and dermatan sulphates
What kind of growth does fibrocartilage undergo?
Only interstitial growth (due to absence of perichondrium)
What is the function of fubricartilage?
Resists deformation under stress (support and tensile strength)
What are the locations of fibrocartilage?
- Intervertebral disc (annulus fibrosus)
- At the pubic symphysis
- Medial and lateral menisci
- Attachment of ligament to bone
- Intersections of some tendons and ligaments
- Articular discs
What are the unique characteristics of fibrocartilage?
- Absence of perichondrium
- Matrix contains type 1 (mainly) & type 2 collagen fibers
- These fibers can be seen here with H & E and trichromatic staining
- Fibers arranged perpendicular to the direction of stress
- Can undergo calcification
- Isogenous groups are in linear fashion (longitudinal columns) due to the compression of collagen fibers
- Doesn’t occur alone, but is found in conjunction with hyaline cartilage and other fibrous tissue
