Cartilage Histology

Question 1

What are the characteristics of cartilage?

Answer 1

Semi-rigid comprised of cells and ECM containg collagen and elastic fibers. It is flexible and resilient, avascular, no nerves

Question 2

What are chondroblasts?

Answer 2

immature cells that secrete cartilage matrix with mitotic capabilities

Question 3

What are chondrocytes?

Answer 3

mature cartilage cells in lacunae, surround by ECM and maintain ECM

Question 4

What fibers make up the ECM?

Answer 4

Type II collagen is predominant, with type I and elastin fibers present

Question 5

What is the ECM mainly composed of?

Answer 5

Hyaluronic acid, chondroitin sulfate, keratin sulfate, aggrecan

Question 6

Describe hyaline cartilage and where it can be found

Answer 6

Glassy, surrounded by perichondrium, contains type II collagen

located in articular cartilage(NO PERICHONDRIUM), larynx, trachea, ribs

Question 7

Describe elastic cartilage and where it can be found

Answer 7

(also contains hyaline) same as hyaline

location: external ear, epiglottis, auditory tube

Question 8

Describe fibrocartilage and where it can be found

Answer 8

Type I collagen, great strength, lacks perichondrium

Located in IV discs, pubic symphysis, TMJ

Question 9

What are isogenous groups which chondrocytes can be found in?

Answer 9

gel-like substance that is uniform but blobby, in lacunae

Question 10

What is territorial matrix?

Answer 10

component of all isogenous groups, territorial matrix is immediately outside of the group, darker stained, consisting of type II collagen, high GAGs

Question 11

What is interterritorial matrix?

Answer 11

component of all isogenous groups, located outside of the territorial matrix, lighter stained, fewer proteoglycans

Question 12

What is perichondrium and what two layers does it have?

Answer 12

It is dense irregular CT, contains vascular supply, in hyaline and elastic cartilage only, source of new cartilage cells

1. fibrous layer
2. chondrogenic layer

Question 13

What is the fibrous layer ?

Answer 13

the outer layer of the perichondrium that produces type I collagen and elastin, transitional zone between cartilage and surrounding general CT

Question 14

What is the chondrogenic layer?

Answer 14

inner layer of perichondrium that differentiates into chondroblasts which secretes type II collagen

Question 15

What does elastic cartilage allow for?

Answer 15

recoil/rebound, retaining shap after deformation, surrounded by perichondrium (contains mix of hyalins and elastic fibers)

Question 16

What are the two types of cartilage growth, chondrogenesis?

Answer 16

appositional and interstitial growth

Question 17

How does appositional growth work?

Answer 17

forms new cartilage on surface of existing cartilage, chondrogenic cells located in inner layer of perichondrium, produce type 2 collagen
forms chondroblasts which secrets type II collagen and ECM

Question 18

How does interstitial growth work?

Answer 18

Takes place within a cartilage mass, the condrocytes divide within lacunae creating new isogenous groups, increasing mass of cartilage

Question 19

Appositional vs. interstitial growth

Answer 19

A: growth of undifferentiated cells of the perichondrium, widen girth
I: new cells added from chondrocytes within isogenous groups, increase overall size, increase length

Question 20

Why does cartilage have limited repair capacity?

Answer 20

Due to the avascular nature

Question 21

How does repair cartilage form and what does it help heal?

Answer 21

Forms when perichondrium is involved: intermediate of hyaline and fibrous cartilage, containing type I and II collagen, can stimulate bone growth

Helps heal bone fractures, age dependent

Question 22

What is the articular capsule?

Answer 22

outer firbous layer made of dense regular CT, strengthens joint

Question 23

What is the difference between extrinsic and intrinsic ligaments of the articular capsule?

Answer 23

Extrinsic is separate from the capsule

Intrinsic is part of the fibrous capsule

Question 24

What is common of articular cartilage?

Answer 24

Avascular, hyaline cartilage, reduces friction, nourished by synovial fluid

Question 25

What is common of the synovial membrane?

Answer 25

contains synovium and reduces friction by fluid, Lines joint except for articular cartilage, vascular, absorbs shock

Question 26

What are the two types of synoviocytes?

Answer 26

Type A macrophage-like and Type B fibroblast-like synovial cells

Question 27

What are characteristic of type A macrophage like synovial cells? (4)

Answer 27

Phagocytic

Contain lysosomes

25% of cells lining synovium

Regulate flammatory events

Question 28

What are characteristic of type B fibroblast-like synovial cells? (3)

Answer 28

Produce synovial fluid

Produce hyaluronate

Lubricates/nourishes articular cartilage

Question 29

What is unique of articular cartilage and what are its different zones?

Answer 29

its collagen fibers run perpendicular to tissue surface and form archs to respond to movement

Superficial (tangential), intermediate (transitional), deep (radial), and calcified zones

Question 30

What is characteristic of the superficial zone of articular cartilage? (3)

Answer 30

Chondrocytes are small and flattened

most superficial is devoid of cells

collagen fibers run parallel to surface

Question 31

What is characteristic of the intermediate zone? (3)

Answer 31

Chondrocytes slightly larger and round

have both alone and isogenous groups

Collagen has oblique course in matrix

Question 32

What is characteristic of the deep zone? (3)

Answer 32

Large condrocytes in radial columns

Stacked perpendicular to surface

fibers follow orientation of chondrocyte columns

Question 33

What is characteristic of the calcified zone? (2)

Answer 33

Rests on cortex of bone

stains darker than the other matrix layers

Question 34

What occurs in early and late stage of osteoarthritis?

Answer 34

Early: superficial layer of articular cartilage is disrupted
Late: destruction of the cartilage extends to bone where the exposed subchondral bone becomes a new articular surface

Common in weight bearing joints and hands