The Human Sense of Smell how we Smell Role of Smell

Smells, aromas, perfumes, all reach our olfactory system under the form of volatile molecules. Such molecules are dispersed in the air and are invisible to our eyes. However, they effectively reach our nose and our brain through several neurons equipped with cilia that allows us to analyze the specific smells. Whether it is bread just baked in the oven, an expensive perfume or some offensive smells caught while passing by a trash can, our brain analyzes the smell and often we are able to react to it.

Smells indeed can make us react in different ways. If the smell is pleasant, we may appreciate it or we may even associate it with far gone memories, if the smell is repulsive our body may even react to it sometimes even stimulating our gagging reflex. There are also smells that can trick us. For instance, that deodorant that makes your home smell so good may not really contain any apples or cinnamon. Indeed, this smell very likely has been created in the laboratory synthetically.

According to the book ”Cadaver Dog Handbook” our olfactory system contains more than 5 million olfactory receptor cells. As much as this number may appear to be impressive, they are relatively a small quantity when compared to the 100 million cells found in a bloodhound’s olfactory system! There indeed is no comparison between the olfactory system of dogs and humans. Apparently, our olfactory system is also going downhill as we are less and less capable of smelling perfumes which are commonly used in larger amounts to compensate.

Our olfactory system is also connected to our sense of taste. For this reason, when we are affected by the common cold or a bout of sinus problems, causing our noses to be stuffed, we may not be able to appreciate foods as we always do. Foods may appear tasteless and dull and this often causes us to lose our sense of appetite. You can experiment this at any time by pinching your nose close and eating your favorite food. You will notice that the food will no longer taste good as you thought.

In another experiment, you can tell a friend to pinch his or her nose shut and close his or her eyes. On one plate you will give a small piece of apple, on the other you will place a small piece of raw onion. Hardly, will your friend notice any difference between the two!

Our sense of smell has also played a role in our ancestral sexual behaviors. We may not notice the effect directly, but pheromones are detected subconsciously and may really play a role in the partner we choose. According to a study, women were offered several t-shirts worn by different men and and most of the women chose t-shirts worn by men that were genetically compatible with them. Indeed, love can really be in the air!

As seen, our sense of smell play various important roles in our lives. So, treat your nose well, do not abuse the use of nasal sprays whichy may cause even a permanent loss of smell and appreciate all the pleasant smells nature has in reserve for you.


Rebmann A, David E, Sorg MH. 2000 Cadaver Dog Handbook: Forensic Training and Tactics for the Recovery of Human Remains. Boca Raton, Florida: CRC Press.

The Pheromone Revolution, retrieved by the World Wide Web on Sept 1, 2009

FDA: Nasal spray may cause loss of smell, CBS news website retreived from the World Wide Web on Sept, 1 2009