Final answer:
Olfactory cells are a specific type of neurons found in the olfactory epithelium in the superior nasal cavity, which detect chemicals as smells and send signals directly to the brain.
Step-by-step explanation:
Olfactory cells are a type of neuron.
Olfaction, or the sense of smell, relies on the olfactory receptor neurons that are situated in the olfactory epithelium, a small region within the superior nasal cavity. These neurons are bipolar, meaning they have two extensions, and are responsible for detecting chemical stimuli in the form of odorant molecules. The olfactory sensory neurons have dendrites with cilia extending into the mucus lining the nasal cavity, where they bind with odorant molecules.
These receptors on the cilia are G protein-coupled, which trigger a graded membrane potential when a specific odorant binds to them. This direct interaction with chemical stimuli allows us to perceive different smells. Olfactory cells not only perceive odorants but also send impulses directly to the olfactory bulb of the brain, bypassing the thalamus, making olfaction unique among the senses.