How does the Human Nose function?

Odors are chemical particles floating in the air. The receptor cells that react to odors are in the upper half of each nostril and within the nasal cavity. They occupy an area about the size of a postage stamp
The receptors have small hairs that lie in mucus. Odors become absorbed in mucus, where they come into contact the receptor cells, called olfactory rods. These send electrical signals to the nerve cells in the olfactory bulb, which sits just above the roof of the nasal cavity, which is protected by a sieve-like plate of bone.