Final answer:
Olfactory hairs refer to the cilia on olfactory cells that have receptors for odor molecules and are responsible for the detection and transmission of smell information to the brain.
Step-by-step explanation:
Olfactory hairs are the cilia on olfactory cells that contain receptors for odor molecules. These are not stiff hairs lining the nasal passages, nor are they the projections on the tongue associated with taste, nor the axons that form the olfactory nerve.
Olfactory receptor cells are located in a mucous membrane at the top of the nose. Small hair-like extensions, these olfactory hairs, from these receptors are where odor molecules dissolved in the mucus interact with chemical receptors located on these extensions. This interaction triggers chemical changes within the cell, resulting in signals being sent directly to the olfactory bulb, which then forwards information to the limbic system and the primary olfactory cortex.
Olfactory neurons are bipolar neurons, and each of these neurons has a single dendrite buried in the olfactory epithelium. Extending from this dendrite are 5 to 20 of these vital cilia that trap odorant molecules. The sensory receptors on these cilia are proteins with varying amino acid chains, making them sensitive to different odorants. Each neuron only contains one type of receptor on its cilia, and these receptors specialize in detecting specific odorants.
When an odorant molecule binds with a receptor that recognizes it, the sensory neuron associated with that receptor is stimulated. This olfactory stimulation is unique in that it directly reaches the cerebral cortex, while other sensory information is relayed through the thalamus.