84
UNIT 2
Basic Tissues
Figure 5-3A.
Hyaline cartilage, trachea.
H&E,
3
68; inset
3
276
This is an example of hyaline cartilage in the trachea. The
hyaline
cartilage
forms a structural framework to support tissues such as
the larynx, trachea, and bronchi in the respiratory tract. The
chon-
drocytes
are mature chondroblasts that are embedded in the matrix.
Each chondrocyte is contained within a small cavity in the matrix
called a
lacuna
; sometimes, one lacuna may contain two cells (Fig.
5-4).
Isogenous
Isogenous
group
group
Isogenous
group
Chondrocytes
Chondrocytes
Chondrocytes
Perichondrium
Perichondrium
Perichondrium
Perichondrium
Perichondrium
Perichondrium
A
Bone
Bone
Hyaline cartilage
Small, flattened
chondrocytes
Joint
cavity
Bone
B
CLINICAL CORRELATION
Figure 5-3C.
Osteoarthritis.
H&E,
3
29
Osteoarthritis
is a chronic condition that is charac-
terized by a gradual loss of hyaline cartilage from the
joints. It commonly affects the hand, knee, hip, spine,
and other weight-supporting joints. Risk factors include
genetic factors, aging, obesity, female gender, injury,
and wear and tear of the joints. Symptoms and signs
include joint pain that is worsened by physical activ-
ity and relieved by rest, morning stiffness, and changes
in the shape of affected joints. There are two types of
osteoarthritides:
idiopathic
and
secondary
.
Idiopathic
has no obvious cause, whereas
secondary
has an identi-
± able cause. Monocyte-derived peptides cause chondro-
cytes to proliferate. Increased numbers of chondrocytes
release degradative enzymes, which cause inadequate
repair responses and subsequent infl
ammation in car-
tilage, bone, and synovium. Cartilage fragments and
soluble proteoglycan and type II collagen can be found
in the synovial fl
uid. This illustration shows the rough
surface of the hyaline cartilage with
f brillations
and
eburnation
as a result of softening, thinning, and loss of
the
articular cartilage
and exposure of the
subchondral
bone
, which becomes worn and polished.
Fibrillation
of articular
cartilage
Eburnation
Subchondral
bone
C
Figure 5-3B.
Hyaline cartilage, f
nger bone.
H&E,
3
68; inset
3
189
This is an example of the
hyaline cartilage
in the articular ends of a
long bone (±
nger bone). The cartilage that covers the articular sur-
face of the bone is called
articular
cartilage
. In this particular region,
the cartilage is exposed without perichondrium present. The surface
area of the articular
cartilage is composed of
small
,
dense
,
attened
chondrocytes
, which enable it to resist pressure and form a smooth
surface to provide free movement in the presence of a lubricating
fl uid (
synovial fl
uid
).
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