Page 22 - ASOP ROT Study Guide

4 . 4 Cartilage
Cartilage consists of cartilage cells, fibers and ground substance. Cartilage is divided into three
types according to the number and type of fibers present. Hyaline cartilage is the most abundant
type of cartilage in the body. It is found lining the ends of bones and joints (articular cartilage), in the
nose, trachea and lungs, and at the ends of the ribs. It contains a small number of collagen fibers,
making it strong but flexible. This structure enables it to play a part in support and, at the joints, to
absorb shock and reduce friction. Fibrocartilage contains very large numbers of collagen fibers
making it very strong and rigid. It is found in the symphysis pubis and the intervertebral discs.
Elastic cartilage contains elastic fibers making it strong and elastic. It is found in the external part of
the ear, maintaining its shape. Unlike bone, cartilage has no blood supply so it takes longer to
repair if damaged. It also has no nerve supply.

4 . 4 . 1 Articular cartilage
Articular cartilage is a form of hyaline cartilage which is present at the end of bones which
articulate in a synovial joint. It consists of a matrix of a non-cellular material known as ground
substance. Within the matrix there are cells, called chondrocytes. These cells are more densely
packed in the deeper layers adjacent to the bone.

Articular cartilage is smooth and provides a low friction surface for the articulating bone ends. It
has a firm consistency but is fairly pliable and has shock absorbing properties. It distributes loads
evenly over a large surface area, reducing contact stress and therefore wear.
This highly specialized tissue has limited regenerative capabilities. The superficial layers of the
cartilage are replaced through regeneration as they wear. However, if the deep layers of cartilage
are lost in an accident, the capacity of articular cartilage to regenerate is limited. The reasons for
this are not fully understood but it is probably because the deeper layers of cartilage have a higher
ratio of cells to matrix and so their loss is more significant.