The Olfactory System

We perceive odors through thousands of olfactory nerves in our nostrils, which contain bundles of highly sensitive nerve cells. Unlike other nerve cells, these cells regenerate every 30 to 40 days. Specific aromatic molecules of essential oils react with specific nerve receptors, which in turn trigger electrochemical impulses that are conducted directly into the brain.

Aromas are transmitted to the limbic system, a part of the brain which perceives and responds to memory, pleasure and emotions. Odor triggers the limbic system to release brain-affecting chemicals known as neurochemicals. Enkephalin reduces pain and creates a feeling of well-being. Endorphins also reduce pain and induce sexual feelings. Serotonin helps relax and calm. Because the olfactory nerves are a direct extension of the brain's limbic system, recognition of smell is relayed immediately, whereas recognition of taste, sound and touch is not as immediate.

The olfactory system of the human brain has a lock and key mechanism for remembering scents. This creates an individual perception of aroma, different preferences for scents and specific memory responses. The lock is the actual smell memory; the key is the scent which opens the mind to the memory. In aromatherapy, the brain responds to the aroma of an essential oil by retrieving a past memory associated with the aroma. If the aroma is unfamiliar, the brain creates a new memory response. The memory responses can be relaxing, balancing, energizing, uplifting, etc. The sense of smell has the longest recall of all senses, so we tend to retain memories associated with aromas for quite some time.