VH 040 Ear

Elastic Cartilage
(Masson's Trichrome / Aldehyde Fuchsin)

Elastic cartilage is similar to hyaline cartilage except that the matrix also contains a dense network of branching and anastomosing elastic fibers. It provides flexible support and is present in the outer ear and epiglottis.

The outer ear (pinna) stained with Masson's trichrome and aldehyde fuchsin. Masson's trichrome stains connective tissue dark blue, smooth muscle and cytoplasm stain light pink, and nuclei stain dark red-purple to black. Aldehyde fuchsin stains elastic fibers pink-purple.

• Perichondrium (blue) - a layer of dense irregular connective tissue that surrounds cartilage. It is divided into two layers:
  • Inner Chondrogenic Layer (darker blue) - contains mesenchymal cells that differentiate into chondroblasts, initiate matrix production (elastin and type II collagen) and become immature chondrocytes
  • Outer Fibrous Layer (blue) - fibroblasts that produce the type I collagen on the outer surface of the perichondrium
• Matrix - composed of an extensive, dark pink-purple network of elastic fibers, type II collagen and a ground substance of proteoglycans.
• Chondrocytes - cells within lacunae inside the cartilage that occur singularly or in clusters called isogenous groups.

Elastic cartilage contains no blood vessels or nerves.