Cartilage Handout

Question 1

locations of hyaline cartilage

Answer 1

nasal, costal, laryngeal, tracheal, bronchial, endplate of bones

Question 2

locations of elastic cartilage

Answer 2

auricular, external auditory meatus, auditory tube, laryngeal, epiglottis

Question 3

locations of fibrocartilage

Answer 3

intervertebral disk, symphysis, articular disks, tendon insertions

Question 4

synovial joints contain what cartilage?

Answer 4

specialized type of hyaline cartilage: articular cartilage

Question 5

chrondrocytes

Answer 5

cartilage cells, produce cartilage matrix. oval/round, basophilic cytoplsm. also secrete enzymes that can degrade CM. maintain integrity of CM.

Question 6

cartilage matrix components

Answer 6

fibers, ground substance, noncollagenous multiadhesive glycoproteins

Question 7

fibers

Answer 7

give mechanical stability to ground substance, predominant type in CM is cartilage-specific collagens

Question 8

type II collagen

Answer 8

predominant isoform of cartilage-specific collagens.

Question 9

cartilage collagens

Answer 9

type II, IX, X and XI. type VI is at periphery of chondrocyte (link btwn chondrocyte and cartilage matrix)

Question 10

type II

Answer 10

most abundant of cartilage-specific collagens, mech stability for matrix

Question 11

type IX

Answer 11

stabilizes type II, facilitating collagen fibril-proteoglycan interaction

Question 12

type X

Answer 12

assoc w hypertrophic regions in cartilage where it organizes collagen fibrils into a 3D lattice

Question 13

type XI

Answer 13

regulates type II fibril size

Question 14

ground substance

Answer 14

hydrated gel: water, ions, proteoglycans (predominant component of CM)

Question 15

aggrecan

Answer 15

predominant proteoglycan monomer

Question 16

multimolecular proteoglycan aggregates

Answer 16

formed by aggrecan monomers bound to central hyaluronate backbone. dense negative charge, keeps them expanded. H20 and Na attracted to neg charges hydrates the CM

Question 17

noncollagenous multiadhesive glycoproteins

Answer 17

components of CM. small regulatory and structural proteins that influence interactions btwn chondrocytes and ECM. chondronectin, tenascin and anchorin CII. markers of cartilage turnover and degeneration.

Question 18

isogenous groups or cell nests

Answer 18

clusters of chondrocytes.

Question 19

lacunae

Answer 19

space w/in CM that chondrocytes occupy

Question 20

chondroclasts

Answer 20

multinucleated cells that degrade calcified cartilage. derived from monocytes, similar to osteoclasts. can give rise to tumors.

Question 21

hormones affecting sulfated GAG synthesis by chondrocytes

Answer 21

increase synthesis: growth hormone, thyroxin, testosterone. decrease synthesis: cortisone, hydrocortisone, estradiol

Question 22

perichondrium

Answer 22

outer part = fibrous connective tissue, type I collagen, secreted by fibroblasts (contains capillary plexus, nerves & lymph). inner part = flattened chondrogenic cells, can become chrondroblasts

Question 23

becoming a chondrocyte

Answer 23

once a chondroblast surrounds itself w cartilage matrix, it becomes a chondrocyte

Question 24

chondroblasts derivation

Answer 24

in embryo, derived directly from mesenchyme

Question 25

nourishment of cartilage

Answer 25

nourished by diffusion thru CM. needs to be hydrated. some water is loosely bound, allowing diffusion. chondrocytes have a high metabolic rate. CM has no lymph or nerve endings.

Question 26

3 types of cartilage

Answer 26

hyaline (most common), elastic, fibrocartilage

Question 27

LM characteristics of hyaline cartilage

Answer 27

homogenous matrix. pericellular matrix surrounds chondrocyte, buffer btwn cell and territorial matrix. interterritorial matrix between lacunae- thick collagen fibers, most of the proteoglycan.

Question 28

specialized types of hyaline cartilage

Answer 28

articular cartilage: covers articular surface. arrangement allows them to distribute compressive forces. no perichondrium (smooth surface). also epiphyseal plates.

Question 29

tidemark

Answer 29

boundary btwn mineralized deep zone and 3 unmineralized zones above it. thick band of mineralized matrix.

Question 30

elastic cartilage

Answer 30

yellowish. chondrocytes are randomly distributed within matrix, hyaline-like matrix surrounds chondrocytes. perichondrium present.

Question 31

fibrocartilage

Answer 31

white, opaque b/c type I collagen. linear arrangement. no perichondrium.

Question 32

2 ways cartilage can grow

Answer 32

interstitial growth (expands from within, in young cartilage w/ more matrix plasticity, imp w/ epiphysial cartilage & long bone growth) AND appositional growth (growth from surface)

Question 33

appositional growth mech

Answer 33

inner layer of perichondrium contains chondrogenic cells which can become chondroblasts that express SOX 9. secrete CM and become enclosed w/in it, and as a result new cartilage is added to surface of existing cartilage element.

Question 34

age related changes to cartilage

Answer 34

affects matrix org, mechanical props & chondrocyte fxn. can get fibrillation, ulceration, chondromalacia.

Question 35

degenerative changes in articular cartilage

Answer 35

arthritis. OA (progressive loss of articular cartilage that can't be repaired) vs RA (inflammatory rxn vs synovium of join, chronic, can lead to destruction of joint. IL-1 and TNF-a cause degradation of core protein w/in proteoglycan aggregates)

Question 36

repair of articular cartilage

Answer 36

injury not extending across tidemark doesn't heal due to lack of influx of chondrogenic cells, fibrin clot or growth factors. if injury extends into bone, repair is incomplete & doesn't restore normal composition/mechanical properties to CM

Question 37

intervertebral discs & degenerative changes

Answer 37

decrease in water d/t decrease in water content in nucleus pulposis & fewer proteoglycans bind water. size of aggrecan molecules decreases. nucleus becomes firm. tears appear in annulus fibrosis. increased probability of mech failure, disk herniation.

Question 38

mineralization of cartilage

Answer 38

CM loses resilience, can occur as a result of aging or pathological change. stiffen matrix, cause loss of resilience.