A Transmission Electron Microscopic Study of the Olfactory Epithelium in Hill Stream Cyprinidiae, Garra mullya (Sykes)

Abstract

Olfaction is primarily produced by the stimulation of receptor cells on the olfactory organ's neuroepithelial surface, surrounded by olfactory nerve fibres. Numerous fish life processes, including migration, communication, feeding, schooling, defence, and reproduction, depend heavily on olfactory signals and cues. The olfactory and reproductory systems are interconnected structurally and functionally, and puberty-related alterations in the olfactory epithelium are documented. The olfactory epithelium, which covers a large portion of the surface of the olfactory rosette, a structure found within the olfactory chambers on the fish rostrum, is where the olfactory receptor cells are situated. Although ultra structural transmission electron microscopic studies of the olfactory organ and bulb are carried out by some investigators but very sparse information is available on hillstream fishes and that is why this work has been undertaken to detail the structure of olfactory system in G. mullya by electron microscopy. Microvillous olfactory receptor cells are placed compactly adjacent to the supporting cell showing a junction complex : the zonula-ocludens. Polygonal white cells are present in between the basal cells and supporting cells. Small polyhedral basal cells lie just above the basal lamina of olfactory epithelium. Basal cells may be working as stem cells for regeneration of lost or damaged non sensory and goblet cells.