The theory of olfaction

Olfaction is a special sense in that odour perception is transmitted directly to the brain. The process of olfaction may be summarised as follows.


The volatile particles of an essential oil evaporate on contact with air.

Some volatile molecules pervade the air and some enter the nose.

The odiferous particles of the essential oil dissolve in the mucous, which lines the inner nasal cavity, prior to their stimulation at the receptor sites.


The captivated aromatic molecules are picked up by the cilia which protrude from the olfactory receptor cells located at the top of the nasal cavity.

The olfactory receptor cells have a long nerve fibre called an axon and an electrochemical message of the aroma is transmitted along the axons of receptor cells to join the olfactory nerves.

The fibres of the olfactory nerves pass through the cribriform plate of the ethmoid bone in the roof of the nose to reach the olfactory bulb, where the odorant signal is chemically converted before being relayed to the brain.

covering entire area of cerebral cortex nasal cavity covering entire area of cerebral cortex nasal cavity

Fig 7.5 Olfaction


Once the message reaches the olfactory bulb, the olfactory impulses pass into the olfactory tract and pass directly to the cerebral cortex where the smell is perceived.

The temporal lobe of the brain contains the primary olfactory area which is directly connected to the limbic area, which is concerned with emotions, memory and sex drive.

The olfactory bulb also connects closely with the hypothalamus, the nerve centre which governs the endocrine system.

Think Clean and Green to Flawless Skin

Think Clean and Green to Flawless Skin

Lets accept the fact: many of us are skin conscious. As much as possible, we wanted to have a fresh, good looking skin. However, many of us failed to recognize that simple steps are the best ways to attain it.

Get My Free Ebook

Post a comment