Different Theories of How We Smell?

The sense of smell, scientifically known as olfaction, uses a sensory organ (nose) to pass scent information on to the olfactory cortex in the brain. Diffuse suspensions of relevant molecules, called odors, are analyzed by the nose using a molecular lock-and-key scheme whereby odors are identified by their unique chemical signatures. Some odor are stronger or more potent than others. Odors in the purest form are much stronger than odors combined in a chemical composition.

Olfactory receptor neurons, are the cells responsible for smell, and are located on a 1-by-2 inch strip of tissue called the olfactory epithelium. The olfactory epithelium is located about 3 inches above and behind the nostrils. The human olfactory epithelium is roughly 16 cm², contrast with some dogs which have 150 cm². This obviously adds the theory behind dogs having a keener sense of smell.

The sense of smell evolved as a means of detecting survival-relevant information about the external world, especially appraising food. Animals such as dogs use their sense of smell for marking their territory as well as finding a mate. Smell is the oldest of the senses, with analogues dating all the way back to the first animals 600 million years ago. One of the five primary senses, smell is most deeply associated with the formation of memories. Dogs use their original memory of a scent to distinguish between safe and dangerous territory.

Humans use smells to refer to memories as well. I will never for get the smell of my gym bag from high school or my moms signature perfume. The smells we encounter in our life are connected with memory of a specific scents initial introduction.