Cartilage Histology

Question 1

What are the cells in cartilage?

Answer 1

chondroblasts

chondrocytes

Question 2

what are chondroblasts?

Answer 2

cells that secrete cartilage matrix

mitotic capabilities

Question 3

What are chondrocytes?

Answer 3

mature cartilage cells in lacunae

surrounded by and maintain matrix

Question 4

What type of collagen is predominant in cartilage matrix?

Answer 4

type II
(type I is in fibrocartilage and outer perichondrium in smaller amounts)

Question 5

What is the ground substance of cartilage made of?

Answer 5

proteoglycans:
hyaluronic acid
chondroitin sulfate
keratin sulfate
aggrecan

Question 6

What are the types of cartilage?

Answer 6

hyaline
elastic
fibrocartilage

Question 7

What characterizes hyaline cartilage/where is it found?

Answer 7

surrounded by perichondrium (except articular)
type II collagen
location: articular cartilage, larynx, trachea, ribs, embryonic dev.

Question 8

Where is elastic cartilage found?

Answer 8

external ear, epiglottis

Question 9

Where is fibrocartilage found?

Answer 9

Location: intervertebral discs, pubic symphysis, TMJ

Question 10

How are chondrocytes arranged in hyaline cartilage?

Answer 10

in isogenous groups

Question 11

What is territorial matrix

Answer 11

immediately surrounding and encompassing isogenous grps
moderately staining (darker than interterritorial matrix)
high GAGs, less collagen

Question 12

What is interterritorial matrix?

Answer 12

surrounds territorial matrix
light staining
more collagen, fewer proteoglycans

Question 13

What is perichondrium?

Answer 13

dense irregular CT = outer boundary of cartilage
contains a vascular supply
NOT on fibrous cartilage
source of new cartilage cells

Question 14

What are the two layers of perichondrium?

Answer 14

Fibrous = outer
chondrogenic = inner

Question 15

What is the fibrous layer of the perichondrium?

Answer 15

outer layer that produces type I collagen and elastin

Question 16

What is the chondrogenic layer of the perichondrium?

Answer 16

inner layer that differentiates into chondroblasts

secretes type II collagen

Question 17

What is elastic cartilage?

Answer 17

hyaline cartilage + elastic fibers w/in matrix
surrounded by perichondrium
elastin stains dark purple/black

Question 18

What characterizes fibrocartilage?

Answer 18

combo of hyaline cartilage and dense regular CT
type I and II collagen
less cartilage matrix
NO perichondrium
withstands compression and shearing

Question 19

What does fibrocartilage look like under microscope?

Answer 19

less matrix
chondrocytes aligned in rows and isogenous grps
fibers oriented in direction of functional stress

Question 20

What is appositional growth?

Answer 20

growth from perichondrium: produce type I collagen
forms new cart on surface of existing cart
growth initiated –> chondroblasts –> secrete type II collagen and ground substance

Question 21

What is interstitial growth?

Answer 21

Takes place w/in cartilage mass
chondrocytes divide w/in lacunae –> more isogenous grps
secrete more matrix –> overall size increase
limited by avascular nature

Question 22

What is repair cartilage?

Answer 22

forms when perichondrium is involved
matrix = in btw of hyaline and fibrous cartilage
types I and II collagen
can stimulate bone growth/ heal bone

Question 23

How is cartilage repair limited?

Answer 23

cartilage is avascular –> repair capacity limited

age dependent

Question 24

What are extrinsic ligaments?

Answer 24

separate from joint capsule

Question 25

What are intrinsic ligaments?

Answer 25

part of fibrous capsule

Question 26

What characterizes articular cartilage?

Answer 26

hyaline cartilage, but NO perichondrium reduces joint friction avascular; no nerve supply nourished by synovial fluid

Question 27

What are the types of synoviocytes?

Answer 27

type A macrophage-like | type B fibroblast-like

Question 28

What characterizes type A macrophage-like synovial cells?

Answer 28

phagocytic contain lysosomes = clear debris 25% of cells lining synovium regulate inflammation

Question 29

What characterizes type B fibroblast-like synovial cells?

Answer 29

produce synovial fluid = plasma filtrate produce hyaluronate lubricates/nourishes articular cartilage

Question 30

What does hyaluronate do?

Answer 30

combines w/ synovial fluid via H2O

Question 31

What are the zones of articular cartilage?

Answer 31

superficial intermediate deep calcified

Question 32

What characterizes the superficial zone of articular cartilage?

Answer 32

chondrocytes small and flattened parallel to surface most superficial region = no cells collagen fibers fun parallel to surface

Question 33

What characterizes the intermediate zone of articular cartilage?

Answer 33

chondrocytes slightly larger and round; alone and in iso grps collagen in oblique course

Question 34

What characterizes the deep zone of articular cartilage?

Answer 34

large chondrocytes in radial columns stacks perpendicular to articulating surface collagen follow orientation of chondrocyte columns

Question 35

What characterizes the calcified zone of articular cartilage?

Answer 35

rests on bone underneath | matrix of this layer stains slightly darker than other layers