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The human primary olfactory pathway: Fine structural and cytochemical aspects during development and in adults
Author(s) -
Chuah Meng Inn,
Zheng Da Ren
Publication year - 1992
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.1070230107
Subject(s) - primary (astronomy) , olfactory system , biology , neuroscience , microbiology and biotechnology , pathology , medicine , physics , astronomy
Despite increasing knowledge about the biophysiology of the human olfactory system, understanding of the development of this pathway in humans lags considerably behind that of other vertebrates. Development studies have largely concentradted on the generation of cell types in the olfactory epithelium during the first trimester, while detailed ultrastructural observations usually describe the adult morphologh. In this review, we have shown that contrary to what has been generally assumed, the surface of the human olfactory epithelium is heterogeneous and that its olfactory nerves differ ultrastructurally from those of other vertebrates studied. The development of the human primary olfactory pathwayis discussed in terms of the appearance of olfactory bulb laminae, synaptogenesis and the expression of specific cell markers, such as the S‐100 protein and olfactory marker protein (OMP). Positive immunohistochemical staining for N‐cadherin in human fetuses suggests that growth ofolfactory axons to their target may be mediated by cell adhesion molecules. The overall data presented here indicate that this pathway develops more precociously in humans than in rodents. Whether this translates also to earlier functional maturity remains to be elecidated. © 1992 Wiley‐Liss, Inc.