The Ultrastructure of the Human Stria Vascularis. PART I

Abstract

The human stria vascularis contains three types of cells (marginal, intermediate and basal) which are remarkably similar to those found in the smaller animals. The narginal cells are rich in a homogeneous electron-dense substance, and contain numerous coated vesicles, mitochondria, rough endoplasmic reticula, and free RNA particles. The luminal surface often shows microvilli and a rather thick unit membrane. Numerous cell processes extend deeply toward the base, interdigitating with those of the intermediate and basal cells. The basement membrane is generally absent except in areas adjacent to the blood vessels. The intermediate cells are rich in Golgi network, smooth and rough endo-plasmic reticula, and large mitochondria. Peripheral to their cell bodies are often short segments of the basement membrane. The basal cells are flat and long and show numerous, short desmosomes and fasciae and maculae occludentes. They send cell processes into the other strial epithelia but desmosomes between them are few. The junction between the basal cells and fibrocytes of the spiral ligament shows desmosomes at random points, and the intercellular space of fibrocytes contains numerous bundles of fibrils which are rectangular in cross section. The blood vessels of the stria vascularis lack smooth muscle cells and neural elements, and about both marginal and intermediate cells.