6.19 - Olfactory System

Abstract

The nose has several critical functions including conditioning inhaled air and olfaction. The nasal passage is lined by olfactory, respiratory, squamous, transitional, and lymphoepithelial epithelium. Each nasal epithelium may be subject to toxicant-induced injury. Toxicant-induced epithelial lesions in the nasal passages are often site-specific and dependent on the intranasal regional dose of the inhaled chemical and the sensitivity of the nasal epithelial tissue to the specific chemical. This chapter focuses on the olfactory system and in particular the olfactory neurons found within the pseudostratified olfactory epithelium. A major difference in nasal epithelium among animal species is the percentage of the nasal airway that is covered by olfactory epithelium. The unique relationship between the olfactory neurons found in the nasal cavity and the brain makes direct delivery of certain xenobiotics to the brain possible. Topics addressed in this review include normal structure and function, olfactory system toxicology, assessment of olfactory function, olfactory toxicants, and olfactory transport. This chapter provides an update of our current understanding of chemically induced olfactory toxicity with a special emphasis on research that is of interest to neurotoxicologists.