Stria Vascularis

Structure and/or Key Feature(s)

The stria vascularis is a complex epithelial structure that is one of the components of the cochlear duct. It overlies the wall of the cochlear duct, adjacent to the spiral ligament. It is a specialized stratified epithelium and, as its name implies, is extensively vascularized. This vascular supply is due to a condensed mesh of capillaries between the epithelial cells.

The stria vascularis is comprised of three main cell types, the marginal cells, intermediate cells, and basal cells. The marginal and basal cells are true epithelial cells, while the intermediate cells are more similar to melanocytes. The marginal cells line the stria vascularis facing directly into the cochlear duct and are involved in ion exchange with the endolymph. The intermediate cells lie below this and are dense in melanin. The basal cells are the deepest cells of the stria vascularis. The marginal cells have descending cytoplasmic extensions, while the intermediate and basal cells have cytoplasmic extensions which project up toward the marginal cells (Standring, 2016).

Function

The stria vascularis aids in the production of endolymph. It plays a role in ion transportation, which facilitates the production of the unique ionic concentration of endolymph resulting in the electrical potential of the endolymph. The reason for its dense vasculature is due to the required maintenance of this potential, which is based on sufficient oxygenation of the epithelial cells. This oxygenation is provided and maintained by the dense vasculature of the stria vascularis.

List of Clinical Correlates

—Sensorineural hearing loss

References

Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice., 41st edition. Elsevier Limited.