Olfaction, which refers to the sense of smell, is a sophisticated system that enables us to perceive different smells around us. It involves several key steps:  

• Odorant Molecules: Volatile (odorant) molecules released from the substances are taken in via the nose when they are sucked through the mouth.  
• Olfactory Receptors: There are millions of specialized olfactory receptor neurons found within the nasal passage. Such neurons, having odorant receptors at their top, comprise specialized nerves. A different smell molecule’s sensitivity is the receptor.
• Signal Transduction: The binding of an odorant molecule with an olfactory neuron receptor triggers a chain of chemical processes. It creates electrical signals in these neurons.  
• Olfactory Bulb: Secondly, the electrical signal is relayed to the olfactory bulb, which is located beneath the brain and has the responsibility of processing smell information.  
• Brain Processing: The information passes through every part of the brain like the limbic system which is responsible for emotion and memory, and the neocortex where it is finally understood. In this way, we are able to get different smells which makes us see them apart.
• Perception: This means that as soon as the brain gets the signals in the form of patterns of electrical activities coming from different olfactory receptor cells, it is able to construct an odor’s perceptions of quality, intensity, and source.