The human endolymphatic sac. An ultrastructural study.

In observing the fine structure of the human endolymphatic sac (ES) by transmission electron microscopy, we defined the cytologic characteristics of the epithelial lining of the various portions of the sac and identified five types of epithelial cells with presumably somewhat different functions. The morphologic findings may suggest that the human ES is involved in endolymph resorption and phagocytosis. In addition, there are indications that in humans the sac may be involved in pressure regulation in the internal ear. The ES has a possible role in the turnover of macular statoconia.