Nose is the main entrance to the respiratory system and is lined with hairy mucous membrane with a lot of capillaries close to the surface. This allows filtering, humidifying and warming inhaled air as he passes the nasal passage and goes to the throat and lungs.

Nasal corridor runs along the top of the palate (the barrier that separates the nose from the mouth) and is rotated down to meet with the passage that leads from the mouth to the throat. However, the nasal passage is not a simple tube. Cavity couples, filled with air (sinuses), branch out from it in the bones of the skull at various points, and in those cavities the nasal mucosa is prolonged. Therefore, nose infection sometimes spread in the sinuses, as well as in other parts of the respiratory system.

The nose is also the organ of smell, and can temporarily lose the ability to detect odors whenever it is shut due to some disorder of the respiratory system. However, the permanent loss of smell (anosmia) is very rare, and to a much lesser extent affects the life than the loss of vision or hearing.