Image of hyaline cartilage from the trachea. Hyaline cartilage is characterized
by the presence of uniformly staining extracellular
matrix composed of fine collagen fibers and polysaccharide-rich proteoglycans.
The cells (chondrocytes) occupy holes in the
matric called lacunae. Note that the chondrocytes
are smaller that the lacunae; this is an artifact of dehydration, which causes
the cells to shrink more that the more rigid matrix.
Where hyaline cartilage is in contact with other tissues, it is covered
by a layer of dense irregular connective tissue called the perichondrium,
containing fibroblasts and blood vessels. The cartilage matrix itself is avascular
(lacks blood vessels). The chondrocytes depend on diffusion of tissue fluid
from the blood vessels located in the perichondrium to supply them with nutrients
and remove waste products.
Beneath the perichondrium is an area of cartilage with lens-shaped (fusiform)
lacunae, occupied by chondroblasts, which are
in the process of producing new cartilage matrix. Further into the cartilage
the lacunae are round and occupied by mature chondrocytes. The martix immediately
surrounding the chondrocytes often stains a differently from the rest of the
matrix, because itis richer in carbohydrates. surrounding and maturing into
rounded chondrocytes.
