olfaction
n. the sense of smell, involving stimulation of receptor cells in the olfactory epithelium (located in the nasal passages) by airborne volatile substances called odorants. Specifically, olfactory receptors extend numerous cilia into the olfactory mucosa in the roof of the nasal cavity; these cilia, together with villi of supporting tissue cells, form a layer of hairlike projections. Molecules of odorants are absorbed into nasal mucus and carried to the olfactory epithelium, where they stimulate the receptor sites of the cilia. The olfactory receptors carry impulses in axonal bundles through tiny holes in the cribriform plate, the bony layer separating the base of the skull from the nasal cavity. On the top surface of the cribriform plate rests the olfactory bulb, which receives the impulses and sends them on to the periamygdaloid cortex. —olfactory
adj.