The olfactory nerve is actually a collection of sensory nerve rootlets that extend down from the olfactory bulb and pass through the many openings of the cribriform plate in the ethmoid bone. These specialized sensory receptive parts of the olfactory nerve are then located in the olfactory mucosa of the upper parts of the nasal cavity. During breathing air molecules attach to the olfactory mucosa and stimulate the olfactory receptors of cranial nerve I and electrical activity is transduced into the olfactory bulb. Olfactory bulb cells then transmit electrical activity to other parts of the central nervous system via the olfactory tract.
The sense of smell is 10,000 times more sensitive than any of the other senses. The human nose is capable of distinguishing between hundreds of thousands of different odors. Without the sense of smell, our capabilities to enjoy food or sex are greatly diminished. Smell is the only sense in which the receptor nerve endings are in direct contact with the outside world.
The olfactory nerve is an extension of the brain itself, reached directly through the nose. This nerve is a direct link to our emotions, memory and learning. Essential oils trigger an olfactory nerve impulse, which goes directly to the brain and produces aromatherapy's far-reaching effects.
