Final answer:
Olfactory receptor cells have hair-like structures called cilia, which are essential for detecting odorants. The sensory receptors on the cilia trap and respond to odour molecules, with signals then sent to the brain's olfactory bulb and further to various regions related to the perception of a smell.
Step-by-step explanation:
Each olfactory receptor cell has a half dozen to a dozen little hairs that project out, called cilia. These hair-like structures are crucial in the process of olfaction, or the sense of smell. The sensory receptors on the cilia are proteins, and each olfactory sensory neuron has one type of receptor on its cilia, specialized to detect specific odorants.
When an odorant binds to a receptor it recognizes, the associated sensory neuron is stimulated, resulting in signals being sent to the olfactory bulb at the tip of the frontal lobe, which in turn sends information to different brain regions such as the limbic system and the primary olfactory cortex.
Olfactory receptor cells are located in the olfactory epithelium within the superior nasal cavity. As odorants enter the nose and dissolve in the mucous, they bind to the odorant-protein complex that further binds to a receptor protein within the cell membrane of the dendrite. These receptors are G protein-coupled and initiate a graded membrane potential in the olfactory neurons.