The Ontogeny of Olfactory Epithelium: An Ultrastructural Study in Sheep

I Kociánová,S Holubcová,A Gorošová,P Čížek,M Buchtová

doi:10.2754/avb200372010003

Abstract

Kocianova I., M. Buchtova, I. Goro‰ova, S. Holubcova, P. âiIek:The Ontogeny of the Olfactory Epithelium: An Ultrastructural Study in Sheep. Acta Vet. Brno 2003, 72: 3-10. Ultrastructure of the olfactory epithelium was studied in ovine foetuses aged 74 and 79 days, in newborn and 30-day-old lambs, and in a 730-day-old sheep. Differentiation of apical parts of supporting cells, cilia on sensory cell dendrite endings, redistribution of centrioles from dendrite into endings and presence of a large amount of glycogen inclusions in supporting cells were apparent at day 74 of the intrauterine development. Supporting cells represented the major portion of the olfactory epithelium at day 79. The epithelial surface was covered by a dense network of cilia, but distal segments were seen only sporadically. The amount of microtubuli increased in dendrite cytoplasm. At birth, the cytoplasm of olfactory endings contained numerous light vesicles, mitochondria and centrioles. The free surface of supportive cells was furrowed into numerous microvilli. Distal segments of olfactory cilia were observed at the age of 30 days only. The segments contained a reduced number of axial microtubuli and contacted microvilli of supporting cells. The pattern and ultrastructure of olfactory cells of an adult sheep did not differ from those of a 30-day-old lamb. Degenerating olfactory cells were observed only sporadically. Supranuclear cytoplasm of supporting cells contained glycogen inclusions and bundles of tonofibrils. Sense organs, transmission electron microscopy, olfactory epithelium, ontogenesis

Highlights

Ultrastructure of the olfactory epithelium was studied in ovine foetuses aged 74 and 79 days, in newborn and 30-day-old lambs, and in a 730-day-old sheep
The structural development of sensory cell and dendrite cytoplasm including its ending has been characterised by C us chieri and Banni st er (1975) as the final maturation of receptory cells
Apparent are an increasing number of microtubuli and progressive redistribution of organelles, above all mitochondria and centrioles, from the dendrite into the nerve ending at the epithelial surface

Summary

Introduction

Ultrastructure of the olfactory epithelium was studied in ovine foetuses aged 74 and 79 days, in newborn and 30-day-old lambs, and in a 730-day-old sheep. Distal segments of olfactory cilia were observed at the age of 30 days only. The ultrastructure of the olfactory epithelium of a variety of mammalian species (Yamamoto 1976; Menco 1977; 1988; Menco et al 1978; Mí‰ek et al 1996; Holubcová et al 1997; Kociánová et al 2001 and others), including humans (Moran et al 1982), has been described and comparative studies have been published (Getchell 1986). Basal cells were regarded as the cell population from which other cell types of the olfactory epithelium differentiate (Moran et al 1982). Information on this topic in companion and farm animals is insufficient

Methods

Results

Conclusion