April 6, 2021

Your sense of smell – much like your sense of taste – is part of your chemosensory system, or the chemical senses. People can smell many, probably thousands of different odors. But how?

Smell reception (Photo: Unsplash)

“Molecules do not have to go all the way to the lungs in order to be smelled, it’s the olfactory receptors in our nose are the ones that pick up the information and send it to our brain for deciphering.”

Whenever we smell something, odor molecules are reaching the olfactory receptors in our nose, where perceiving smell begins. In order that we can smell odors, odor molecules have to reach the inside of our nose, the nasal cavity. This usually happens when we breathe in. During every breath, the air surrounding us is soaked into our lungs. Dr. Johannes Frasnelli says, odor molecules do not have to go all the way to the lungs in order to be smelled. Instead they just have to reach the so called olfactory mucosa, which is located in the nasal cavity.

“In the brain, smell is deciphered in two spheres: 1st the primitive brain that processes emotions and memory- LIMBIC BRAIN and 2nd in the thinking brain that translates into motivational forces and behaviour- NEO-COTEX.”

As every opening of our body, the nasal cavity is lined with mucosa. The nasal mucosa carries certain cells, the olfactory receptor cells, which detect the odor. The olfactory receptor neurons transmit the information to the olfactory bulbs, which are located at the back of the nose. The olfactory bulbs has sensory receptors that are actually part of the brain which send messages directly to:

  • The most primitive brain centers where they influence emotions and memories (limbic system structures), and
  • The translating sensory data from the neo-cortex (the thinking brain), which translates into motivational forces for behavior.

Brain structure (Photo: Medium)

The limbic system comprises a set of structures within the brain that are regarded by scientists as playing a major role in controlling mood, memory, behaviour and emotion. It is often regarded as being the old, or primitive, part of the brain, because these same structures were present within the brains of the very first mammals. Knowing this helps us to understand why smell plays such an important role in memory, mood and emotion.

Given that our sense of smell clearly plays an important part in our psychological make-up, in addition to it being one of the five ways in which we connect with the world around us, its absence can have a profound impact.

For example, your sense of smell often serves as a first warning signal, alerting you to the smoke of a fire, spoiled food, or the odor of a natural gas leak or dangerous fumes. Moreover, smell loss – also known as Ansomia – can affect one’s ability to form and maintain close personal relationships, which can lead to depression.

Depression (Photo: Unsplash)

Ansomia may also be a sign of other serious health conditions, so if you’re  experiencing any smell disorders, do not hesitate and talk with your doctor.