Blood Supply and Function of the Tegmentum Vasculosum (Stria Vascularis) of the Duckling Cochlea

On the basis of ultrastructural, biochemical, cytochemical, and electro-physiological evidence, the stria vascularis, a highly vascular epithelium of the mammalian cochlea, has been implicated as one site of endolymph synthesis. It would seem natural to suspect that its highly developed counterpart in the avian cochlea, the tegmentum vasculosum (TV), might have a similar function. This study utilizes routine light and electron microscopy, biochemistry, cytochemistry, and vascular corrosion casting to describe the structure and blood supply to the (TV) in the duckling and provide evidence for its involvement in endolymph synthesis.Four to 16 week-old ducklings (Anas platyrhyncos)were anesthetized and anticoagulated and perfused via the common carotid arteries with buffered, 2% glutaraldehyde for routine light microscopy or transmission or scanning electron microscopy, or with Mercox resin for vascular corrosion casting. Casts were macerated in 5% KOH and warm water to remove tissue, cleaned in formic acid and water, dried by lyophilization, mounted on stubs and viewed at 10-20 kv by SEM.

Specialized Epithelia in the Avian Labyrinth (Its Distribution and Ultrastructure)

In recently years the distribution of the non-sensory specialized epithella in the inner ear has been interested among otologists. Increased understanding of the problem dealing with the fluid transport within the endolymph has been obtained these studied. To our knowledge, however, the distribution of the avian specialized cells in the inner ear has not been described adequately. In addition, ultrastructural characteristics of the osmiophilic(dark) cells in the avian labyrinth were not clearly demonstrated. Therefore, the specialized epithlia in the avian labyrinth should be further investigated and the nature of their function defined.To demonstrat this, pigeois were investigated using phase and electron-microscopy. The specialized cells(dark and light cells) were distributed in the crlstae ampullaris, the tegmentum vasculosum of the lagena which is analogous to the stria vascularis in mammals, the saccule, the otolith lagena, the utricle and the crista negletica.