Cartilage Flashcards
All cartilage posses perichondrium except for: (3 things)
- epiphyseal growth plate
- fibro-cartilage
- articular cartilage
Which type of cartilage growth occurs by differentiation of perichondrial fibroblasts into chondrocytes and chondroblasts?
Appositional Growth
Which type of cartilage growth occurs by mitosis of existing chondroblasts and chondrocytes and is restricted only to those sites without a perichondrium?
Interstitial growth
What are the four characteristics of the perichondrium?
- All cartilage posses perichondrium (except epiphyseal growth plate, fibro and articular cartilage)
- Essential for appositional growth
- Provides nutrients
- Sox transcription factors induce differentiation into chrondroblasts
Interstitial Growth occurs in cartilage that lack a ?
perichondrium
Interstitial growth occurs as a functional growth hormone from the (Somatotropin):
pituitary that stimulates somatomedin C from liver that stimulates mitosis of chondroblasts and chondrocytes
Achondroplasia?
- no cartilage growth
2. typically presents as dwarfism
Hyaline cartilage contains no blood vessels referring to?
avascular
clusters of cell in isogenous cartilage can be formed by?
interstitial growth
A chunk of the cartilage that breaks can cause pain because there is free floating cartilage that is getting caught in your articular joint (damage of cartilage covering articulating surfaces), which refers to?
Osteoarthritis
Swelling of the membranes which puts pressure on the joints refers to?
rheumatoid arthritis
Characteristics of Hyaline cartilage:
- Type II collagen
- basophilic matrix
- chondrocytes usually arranged in groups
(perichondrium present in most places; except for articular cartilages and epiphses)
Characteristics of Elastic Cartilage:
- Type II collagen
- elastic fibers
(perichondrium present)
Characteristics of Fibrocartilage:
- Type II collagen
- acidophilic matrix
- chondrocytes arranged in parallel rows between bundles of collagen
- always associated with dense regular collagenous connective tissue or hyaline cartilage
(perichondrium absent)
Where is Hyaline cartilage located?
Articular ends of long bones, nose, larynx, trachea, bronchi, ventral ends of ribs
Where is elastic cartilage located?
Pinna of ear, walls of auditory canal, auditory tube, epiglottis, cuneiform cartilage of larynx
Where is fibrocartilage located?
Intervertebral disks, articular disks, pubic symphysis, insertion of some tendons
Characteristics of cartilage (4)
- Amorphous ECM predominates over fibrous ECM
- Rich in Proteoglycans
- Functions in Support and Flexibility for sliding of joints, as a shock absorber and growth of long bones
- Presence declines from fetus to adult (follows evolution of the vertebrates)
Components of cartilage: cellular
a) Perichondrial fibroblasts
b) Chondroblasts
c) Chondrocytes
d) Chondroclasts (i.e. osteoblasts)
Components of cartilage: Extracellular Matrix (40%)
- Amorphous matrix predominates – mostly glycosaminoglycans, proteoglycans (aggrecan, syndecan, fibroglycan) and glycoproteins (chondronectin, chondrocalcin)
- Fibrous component less prominent with mostly Type II collagen (hyaline cartilage), Type I collagen (fibrocartilage) and elastic fibers (elastic cartilage)
Characteristics of chondroclasts (4)
- associated with cartilage resorption
- similar to osteoclasts in morphology and function
- In endochondral ossification, their function is to remove calcified cartilage
- appear to enter cartilage with vasculature (may derive from monoctyes)
Characteristics of Non-Vascularity of Cartilage (3)
- No blood supply - channels form fracture planes
- Diffusion is rate limiting to thickness of cartilage
- Damage/loss of cartilage difficult to regenerate
Characteristics of Interstitial Growth - Mitosis
- Occurs in cartilage that lack a perichondrium i.e. epiphyseal growth plate, articular cartilage and fibrocartilage
- Mitosis of pre-existing cells
- Somatotropin (GH) from anterior pituitary stimulates somatomedin C from liver that stimulates mitosis of chondroblasts and chondrocytes
Hyaline Cartilage has the following features:
- avascular
- surrounded by perichondrium (except in articular cartilage). The perichondrium has an outer fibroud layer, an inner chondrogenic layer and blood vessels
- consists of chondrocytes surrounded by territorial and interterritorial matrices containing type II collagen interacting with proteoglycans.
- it occurs in the temporary skeleton of the embryo, articular and the cartilage of the respiratory tract (nose, larynx, trachea and bronchi) and coastal cartilages.
Elastic cartilage has the following features:
- avascular
- surrounded by perichondrium
- consists of chondrocytes surrounded by territorial and interterritorial matrices containing type II collagen interacting with proteoglycans and elastic fibers, which can be stained by orcein for light microscopy.
- occurs in the external ear, epiglottis and auditory tube
Fibrocartilage has the following features:
- avascular
- lacks a perichondrium
- consists of chondrocytes and fibroblasts surrounded by type I collagen and a less rigid extracellular matrix. Fibrocartilage is considered an intermediate tissue between hyaline cartilage and dense fibrous tissue.
- predominates in the intervertebral disks, articular disks of the knee, mandible, sternoclavicular joints and pubic symphysis
