Embryologic Development in Vivo and in Vitro of the Dark Cell Region of the Mammalian Crista Ampullaris

Abstract

The area comprising the dark cells around vestibular organs was analysed with regard to embryologic development and maturation from the 13th gestational day (otocyst stage) (CBA/CBA mouse) to birth at the 21st gestational day when the organ reveals a morphologic maturation of inner ear gross structure and as also cytodif-ferentiation of vestibular hair cells. The development occurred parallel in vivo and in vitro. Electron-optically dense pigments below the dark cell region were first identified on the 15th gestational day. On the 16th gestational day the future dark cells have their mitochondria accumulated to the infranuclear region of the cell. From the 17th day onward, intercellular spaces develop close to the basal membrane, forming at birth a meshwork of interdigitations. Prior to birth the future dark cells reveal an increase in electron density after staining. At birth the morphological configuration of the dark cell area appeared quite mature.