olfactory receptor neurons

An olfactory receptor neuron (ORN), also called an olfactory sensory neuron (OSN), is a sensory neuron within the olfactory system. ORNs are the principal neurons of the sense of smell: they detect volatile chemicals in inhaled air and convert that chemical signal into an electrical one that is relayed to the olfactory bulb of the brain. Unusually for neurons, ORNs are continually replaced throughout life from stem cells in the olfactory epithelium.