How smell works

• Odour molecules that move through the air up your nostrils will bind to special smell receptors on the surface of nerve cells.
• The nerve cells send a signal to the brain's olfactory bulb, that is behind the bridge of the nose.
• People have about 400 different smell receptor types.
• The odour molecules create a pattern of activation in the nerve cells that the brain translates as a smell.

A complete loss of smell, known as anosmia, can occur after a cold, sinus infection or even a bump to the head.

Anosmia affects the flavour of food. However, it isn't always permanent and may recover naturally or through exercises like 'smell training' to ...