Lecture 8: Microanatomy of Cartilage

Question 1

embyronic origin of cartilage (and bone)

Answer 1

mesenchyme from mesoderm

Question 2

chondrogenic cells

Answer 2

cartilage stem cells

Question 3

articular cartilage definition

Answer 3

hyaline cartilage with NO perichondrium

Question 4

what 2 types of cartilage have perichondrium

Answer 4

elastic
hyaline

Question 5

perichondrium definition

Answer 5

dense CT surrounding elastic and hyaline cartilage

Question 6

what 2 types of cartilage are not surrounded by perichondrium

Answer 6

fibrocartilage
articular cartilage

Question 7

2 layers of perichondrium

Answer 7

outer fibrous layer
inner cellular layer

Question 8

components/features of outer fibrous layer: perichondrium

Answer 8

type 1 collagen
dense CT
fibroblasts
VASCULATURE

Question 9

when no perichondrium is present, where are nutrients received from

Answer 9

synovial fluid

Question 10

component of inner cellular layer: perichondrium

Answer 10

chondrogenic cells

Question 11

Chondrocyte definition/function

Answer 11

Specialized fibrocyte producing cartilage ECM
Quiescent

Question 12

Chondrocytes vs chondroblasts

Answer 12

Chondroblasts are ACTIVELY secreting ECM

Question 13

How is lacuna formed

Answer 13

ECM forms around chondroblast

Question 14

Lacuna definition

Answer 14

Fluid filled space where quiescent chondrocyte resides

Question 15

2 ways cartilage grows

Answer 15

Appositional growth
Interstitial growth

Question 16

Appositional growth process

Answer 16

Chondrogenic cells in perichondrium undergo mitosis and differentiate into chondrocytes/chondroblasts that secrete ECM
New cells and ECM added to edge of pre existing tissue (on outer surface)

Question 17

Interstitial growth process/features

Answer 17

Chondrocytes undergo mitosis to produce daughter cells that stay close to each other and form isogenous groups
Isogenous groups produce ECM and get pushed apart
New cells and ECM added within tissue
Growth occurs in any direction

Question 18

Isogenous group definition

Answer 18

Collection of Chondrocyte daughter cells that remain close together

Question 19

In what kind of cartilage growth process can growth occur in any direction

Answer 19

Interstitial

Question 20

Extracellular matrix definition

Answer 20

Mostly water
Supported by collagen fibers
Secreted by chondroblasts

Question 21

Is cartilage vascular

Answer 21

No

Question 22

How does cartilage receive blood supply

Answer 22

Nearby CT = perichondrium, joint capsule (synovia)

Question 23

What helps cartilage regulate fluid content and resist compression

Answer 23

Avascularity
ECM

Question 24

Proteoglycans definition

Answer 24

Protein bound to glycosaminoglycans

Question 25

Glycosaminoglycans function

Answer 25

Attract water

Question 26

Proteoglycan aggregates: definition, function, location (general)

Answer 26

Aggregates of proteoglycans bound to hyaluronic acid in ECM In cartilage Create internal pressure that allows cartilage to resist compression without inhibiting flexibility —> TURGOR

Question 27

Main structural components of cartilage (4)

Answer 27

Mostly water Cells Collagens Glycosaminoglycans and proteoglycans

Question 28

3 regions of ECM

Answer 28

Capsular matrix Territorial matrix Inter territorial matrix

Question 29

Capsular matrix of ECM: amount of proteoglycans, stain color, relation to chondrocytes

Answer 29

Around/surround chondrocytes Many proteoglycans Stain very dark purple

Question 30

Territorial matrix of ECM: amount of PG’s, stain color, relation to chondrocytes

Answer 30

Near chondrocytes Type II fibrils, PGs Dark staining (but not as dark as capsular matrix)

Question 31

Inter territorial matrix of ECM: amount of PG’s, stain color, relation to chondrocytes

Answer 31

Few PG’s Away from chondrocytes Pale staining

Question 32

What stain must be used to indefinite elastic fibers

Answer 32

Verhoeff’s or orcein

Question 33

PG’s vs collagen in cartilage stain what color

Answer 33

Purple for PGs Pink for collagen

Question 34

Elastic cartilage requires added

Answer 34

Flexibility

Question 35

Fibrocartilage must be able to

Answer 35

Resist tension

Question 36

What kind of cartilage is found in intervertebral disc

Answer 36

Fibrocartilage

Question 37

What kind of cartilage is found inside the trachea

Answer 37

Hyaline

Question 38

What kind of fibers are never present in hyaline ECM

Answer 38

Type 1 collagen Elastic

Question 39

articular cartilage definition

Answer 39

type of hyaline cartilage found on surfaces of synovial joints

Question 40

articular cartilage lacks (3)

Answer 40

perichondrium type 1 collagen elastic fibers

Question 41

subchondral bone

Answer 41

bone supporting articular cartilage covered completely in cartilage

Question 42

balanced steady state of chondrocytes in cartilage

Answer 42

synthesis/anabolic of ECM components in equilibrium with normal turnover/catabolism of matrix molecules

Question 43

damage to cartilage matrix: how it affects balance

Answer 43

chondrocytes release more cytokines that inhibit ECM secretion and enzymes that digest ECM vs factors that produce more matrix --> cartilage degeneration

Question 44

can articular cartilage repair/scar... why or why not

Answer 44

no no perichondrium

Question 45

repair of damaged cartilage tissue can be initiated where

Answer 45

perichondrium