Smell is a very direct sense. In order for us to smell something, the item must distribute molecules into the air. These molecules are light, volatile chemicals that float through the air and into our nasal passages. Does everything have a smell? The short answer is “no,” because not all materials give off molecules. An example is a bar of steel, it has no smell because nothing evaporates from it, it is a non-volatile solid.
So how does our sense of smell work? At the top of our nasal passages, behnd the nose, is a patch of special neurons about the size of a postage stamp. These neurons are unique in that they are exposed to air and they have small hair-like projections called cilia that increase their surface area. When an odor molecule comes in contact with the cilia, it triggers the neuron, and you perceive the smell.
Humans are able to distinguish over 10,000 different odor molecules. We use our sense of smell in a variety of activities from enjoying freshed baked cookies, to deciding who we sit next to in a room. The sense of smell is directly linked to feelings such as relaxation, sensuality, happiness and self-confidence. It plays an essential role in who we are attracted to. How does this happen? When we smell, the odor stimulates the olfactory pathways to the limbic system which is also called the “pleasure center,” of the brain. This is were we store our feelings.
Odor also plays an important role in jogging one’s memory. Have you ever walked past a bakery and thought, “oh that smells like grandma’s house?” Or smell a certain after-shave lotion and think, “that reminds me of my dad?”
Here are some interesting facts about the sense of smell…
- All flavors come from smell. Without the sense of smell you can’t taste the difference between an apple or an onion.
- A physical attraction between two human beings depends more on smell than on any other attribute.
- Olfactory cells are renewed every 28 days, so every month you get a new nose.
- Our sense of smell is more connected to emotion than any other sense.
- Smells can alter and influence our moods and behaviors.
- There are some websites dedicated to explaining our sense of smell such as the Sense of Smell Institute.