1.
2 ways in which cartilage grows?: * Apposition - differentiation of mesenchymal perichondrial cells (also mitosis)
* Interstitial - mitosis of chondrocytes and deposition of new matrix (occurs in early phases)
2.
cauliflower ear?: collection of fluid in external ear UNDER PERICHONDRIUM
separating the cart from its nutrient supply so cells die and form scar tissue
permanent condition
3.
effect of having too much Vit A in cart growth?: accelerate ossification of epiphyseal plates
4.
effect of too little Vit A on cart growth?: reduced width of epiphyseal plates
5.
function of elastic cartilage?: recoil- it's in external ear and epiglottis
6.
function of fibrous cart?: resists tension (like between bone and tendon)
tensile strength = don't stretch much but don't break when stretched
7.
function of hyaline?: *resists compression that's why it's articular cartilage
*responsible for the longitudinal growth of bones
*in embryo is serves as temporary skeleton until replaced by bone
8.
how do elastic fibers appear under special LM stain?: they have higher density around chondroblasts (don't forget to look at all the LM images in the lectures)
9.
how does fresh hyaline cart look like?
compare to elastic cart?: hyaline is bluish white and translucent
elastic is yellowish
10.
How is elastic cart different from hyaline cart?: its matrix and perichondrium also contain elastic fibers
ELASTIC cart does NOT undergo calcification unlike hyaline and fibrocart
11.
how to differentiate between fibroblasts and chondrocytes on LM?: fibroblasts are elongated and lined in rows
chondrocytes are numerous and have round nuclei
12.
micrograph of fibrous cart shows variation in staining based on what?: based on conc of collagen, darker purple in terretorial matrix because of high conc of GAGs
light purple in interterretorial matrix because of less GAG
13.
on what hormone does cartilage growth mainly depend?: it depends on the hypophyseal growth hor mone SOMATOTROPIN (>somatomedin C in liver > chondrocytes)
14.
so whats the molecular basis of its elasticity?: glycoprotein subunits are joined by covalent bonds, produces elastin network like a rubber band
(we don't need to know details =])
15.
the cartilage in fibrocartilage is only around the _______ cells, the rest of the tissue is_______: around the chondrocytes, the rest is dense CT with blood vessels.
16.
type of fibers in elastic cart?: col type 2 and elastic fibers
17.
type of fibers in fibrous cart?: col type 1 secreted by fibroblasts
and type 2 secreted by chondroblasts (this is dominant in the matrix)
18.
type of fibers in hyaline cart?: type 2 collagen
has aggrecan and chondronectin
19.
what cartilage does not have perichondrium?: *articular hyaline cart (comes in contact with synovial fluid and receives nutrients from it)
*fibrocartilage does not have a perichon (most hyaline and elastic cart do)
20.
what does too little Vit C do to cart growth?: inhibits matrix synthesis and deforms epiphyseal plates leading to scurvy
21.
what is endochondral ossification: gradual replacement of cartilage to bone
22.
What is the effect in absence of Vit D? on cartilage: proliferation in chondrocytes is NORMAL
matrix does NOT become calcified > leading to rickets
23.
what is the nucleus pulposus made from?: cells from notochord forming a gel
it has collagen and hydrated proteoglycans but NOT cartilage
24.
what is the structural feature that allows articular cart to resist compression?: collagen fibers are first perpendicular and then bend gradually forming an arch parallel to surface
25.
what slows down GAG synthesis by chondrocytes thus inhibiting cart growth and matrix formation: cortisone, hydrocortisone, estradiol
26.
what stain is used for intervertebral disc collagen?: trichrome stain, stains them green
27.
what stimulate chondrocytes to synthesize sulfated GAGs, making cart grow and make matrix: GH, thyroxin, testosterone (thats why men grow more than women)
28.
where does appositional growth occur?: between cart proper and surrounding perichon
AT THE EDGEs thus responsible for final shape
29.
where does interstitial growth of cart occur?: epiphyseal plates of long bones
articular cart (because theres no perichondrium)
IN THE MIDDLE OF MASS thus responsible for inc in overall size
30.
why does damaged cart undergo slow and incomplete repair? (except in young children): cuz of avascularity and immobility of chondrocytes
31.
why does elastic cart need to be elastic!: cuz its subjected to repeated deformation and vibration
