How does our sense of smell work?

Your nose reacts to chemical stimuli. Food releases volatile molecules into the air. Although you cannot see them, your nose can smell them.

When these molecules reach the back of your nose, they are detected by your olfactory receptors, located on the olfactory cilia of your olfactory cells.

Your olfactory nerve then transmits the information to your brain.

Perceiving odours
What is orthonasal olfaction?
When olfactory molecules reach your nose through the air you breathe, this is called orthonasal olfaction.

Perceiving aromas
What is retronasal olfaction?
We also perceive olfactory molecules via the retronasal pathway, which means via the buccal cavity. As food is heated up and chewed, it releases olfactory molecules which move up through the pharynx to reach the olfactory receptors.

How can we distinguish between ODOURS and AROMAS?

We perceive odours when we smell food and the molecules travel through the nose. We perceive aromas when we eat or drink and the molecules travel through the back of the mouth.