CHAPTER 5
Cartilage and Bone
83
D. Cui /T. Yang
Chondrocyte
Territorial matrix
Type II collagen
Interterritorial matrix
Isogenous group
Chondroblast
Chondrogenic cell
Inner cellular layer
of the perichondrium
Outer fibrous layer
of the perichondrium
A
Chondrocytes
Chondrocytes
Isogenous
Isogenous
group
group
Chondrocytes
Chondroblasts
Isogenous
group
Perichondrium
Chondroblasts
B
Chondrocytes
Chondrocytes
Interterritorial
Interterritorial
matrix
matrix
Chondrocytes
Interterritorial
matrix
Territorial
Territorial
matrix
matrix
Territorial
matrix
C
Figure 5-2A.
A representation of hyaline cartilage.
Hyaline cartilage
is the most common of the three types of
cartilage (hyaline cartilage, elastic cartilage, and F
brocar-
tilage). It can be found in the trachea, bronchi, distal ends
of ribs, and articular ends and epiphyseal plates of long
bones. Most hyaline cartilage is covered by
perichondrium
,
a dense irregular connective tissue sheath. However, the
hyaline cartilage in the articular joint surfaces of long bones
is an exception (±ig. 5-3B). Hyaline cartilage is composed
of chondroblasts, chondrocytes, delicate
collagen
(
type II
collagen
), and a homogenous
ground substance
(
matrix
),
which makes it
glassy
in appearance. The matrices include
the
territorial matrix
and the
interterritorial matrix
.
Figure 5-2B.
Hyaline cartilage, bronchus.
H&E,
3
139; inset
3
167
This is an example of
hyaline cartilage
in the bronchus.
Cartilage is an
avascular tissue
; nutrients are supplied
through matrix diffusion. The
perichondrium
, a dense
irregular connective tissue sheath surrounding the surface
of the hyaline cartilage, provides the nearest blood sup-
ply to the cartilage. The perichondrium consists of (1) an
outer ± brous layer
, which is composed of type I collagen,
F broblasts, and blood vessels and (2) an
inner
cellular
layer
, which contains chondrogenic cells that give rise to
new
chondroblasts
. These cells are fl
attened cells, which
actively secrete matrix and often are located beneath the
perichondrium (±ig. 5-2A). Chondrogenic cells are dif-
F cult to identify under the light microscope with H&E
stain. The chondrocytes are often arranged in small clus-
ters called
isogenous groups
, which contribute to intersti-
tial growth (±igs. 5-2A and 5-3A).
Figure 5-2C.
Hyaline cartilage, bronchus.
H&E,
3
136;
inset
3
251
The
chondrocytes
have small, round nuclei and shrunken,
pale-staining cytoplasm, which contains large Golgi appa-
ratuses and lipid droplets. The matrix that surrounds each
chondrocyte or isogenous group is called the
territorial
matrix
. The matrix that F
lls in the space between isoge-
nous groups and chondrocytes is called the
interterritorial
matrix
(±ig. 5-2A). In general, the territorial matrix stains
darker than the interterritorial matrix in H&E.
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