Cartilage Histology

THREE CARTILAGE TYPES

Hyaline, elastic, and fibrocartilage

  • Cartilage type is determined by matrix and fiber components.

Hylaine Cartilage

The most common type in the body.

Matrix

  • Glassy, pink-staining, gel-like matrix comprises a ground substance of proteoglycan aggregates, chondronectin, and water.

Isogenous groups of chondrocytes are housed within lacunae; the darker staining ring around the lacuna is the cartilage capsule.

Invisible type II collagen fibers.

Locations:

  • Sternal ends of the ribs, many articular surfaces, the tracheal rings, the larynx, and the nasal septum.
  • Hyaline cartilage is also the skeletal precursor during development.

Functions:

  • At the articular surfaces, hyaline cartilage provides a smooth surface for free movement; elsewhere, such as in the nasal septum, it provides structural support.

Elastic Cartilage

Shares many similarities with hyaline cartilage.

Matrix

  • Very light staining

Chondrocytes in lacunae

Elastic fibers create a dark-staining network around the lacunae

Locations:

  • Auditory tubes, epiglottis, and external ear

Functions

  • Elastic fibers provide flexibility with recoil; for example, when you bend your external ear, it moves easily, but snaps back into place when released.

Fibrocartilage (aka, fibrous cartilage)

Highly organized appearance.

Collagen fibers

  • Tightly packed, thick bundles of type I and type II collagen fibers run in parallel.

Lacunae and chondrocytes lie in rows between the collagen bundles.

Locations

  • Intervertebral discs, the pubic symphysis, and the joint capsules

Functions:

  • Provides tensile strength and resistance to compression; its dense nature allows it to bear a weight, as in the intervertebral discs.

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