Hyaline cartilage (articular
cartilage) consists of a slimy mass of a firm consistency,
but of considerable elasticity and pearly bluish color.
It contains no nerves or blood vessels, and its structure
is relatively simple. Except where it coats the skin and
the articular ends of bones, it is covered externally
by a fibrous membrane, the perichondrium. This membrane
contains vessels that provide the cartilage with nutrition.
If a thin slice is examined under the microscope, it will
be found to consist of cells of a rounded or bluntly angular
form, lying in groups of two or more in a granular or
almost homogeneous matrix.
The cells, when arranged in groups of two or more, have
generally straight outlines where they are in contact
with each other, and in the rest of their circumference
are rounded. They consist of clear translucent protoplasm
in which fine interlacing filaments and minute granules
are sometimes present; embedded in this are one or two
round nuclei, having the usual intranuclear network. The
cells are contained in cavities in the matrix, called
cartilage lacunae; around these the matrix is arranged
in concentric lines, as if it had been formed in successive
portions around the cartilage cells. This constitutes
the so-called capsule of the space
Each lacuna is generally occupied by a single cell, but
during the division of the cells it may contain two, four,
or eight cells.
Hyaline cartilage also contains chondrocytes, which are
cartilage cells that produce the matrix. Hyaline cartilage
matrix is mostly made up of type II collagen and Chondroitin
sulfate, both of which are also found in elastic cartilage.
