Development of the tectorial membrane

During development, the organization of the stereociliary bundles undergoes drastic changes from the microvilli-like nascent stereocilia to the ' W ' formation of the step-like arrangement of the adult form. During this period the developing tectorial membrane (TM) establishes prescribed attachments with various substructures of the developing sensory ciliary bundles and supporting cells. The TM detaches from the supporting cells and inner hair cell stereociliary bundles as Kölliker's organ matures. The inter-connecting linkage system develops postnatally, and the ' tip-linkages ' are already found in one-week-old mice, suggesting that the critical organization of the micromechanics of the stereocilia matures rapidly during the postnatal period. The TM develops in stages, and its development parallels that of the organ of Corti. The major TM is initially secreted by the greater epithelial ridge cells, and the minor TM is produced by the lesser epithelial ridge cells. The substructures of the TM are formed by the participation of a number of different supporting cells. During the active stage of production of the substructures by the supporting cells, these cells are intensely Alcian blue-PAS stained, indicating that the glycoconjugates are locally produced by these cells.