What are the different types of cells in the nose

The nasal cavity refers to the interior of the nose or the structure which opens exteriorly at the nostrils. It is the entry point for inspired air and the first of a series of structures which form the respiratory system. The cavity is entirely lined by the nasal mucosa, one of the anatomical structures (others include skin, body encasements like the skull and non-nasal mucosae such as those of the vagina and bowel) which form the physical barriers of the body’s immune system. These barriers provide mechanical protection from the invasion of infectious and allergenic pathogens.

Humans can smell thousands—perhaps even millions—of different scents. Yet scientists know that in the nose, there are only about 400 different types of odour receptors—proteins that capture scented molecules so that smells can be identified. Thus, there isn’t, obviously, one type of receptor that responds to a rose, while another jumps for jasmine.

So how can we smell so much, with so few types of receptors?

The answer is that cells mix and match. Each nerve cell in the nose can sense more than one odour but picks up the smell to a different degree. An odour's unique signature depends on which cells respond to it, and how intensely.

What happens when you inhale a rose is that a group of cells is stimulated, and that group sends a combination of signals to the olfactory bulb—the site at the very front of the brain where smell perception takes place. This unique combination of signals tells the brain the odour is the smell of a rose.

What are the different types of cells in the nose

The epithelium of the nasal mucosa is of two types – respiratory epithelium, and olfactory epithelium differing according to its functions. In the respiratory region, it is columnar and ciliated. Interspersed among the columnar cells are goblet or mucin cells, while between their bases are found smaller pyramidal cells.