Olfactory System:

The olfactory system (smell) and the gustatory system (taste) are connected as the chemosensory system — both give the brain information about the chemical composition of stimuli (odorants). Specialized tissue in the nasal cavity (olfactory epithelium /OE) contains olfactory receptor neurons that interact with odorants — causing the sense of smell. The olfactory system, made up of the OE, olfactory bulb, and olfactory cortex, contains 6–20 million olfactory receptor neurons. It has the body’s shortest sensory nerve, running from the brain to the upper part of our nose. It’s part of both the peripheral and autonomic nervous systems. Smelling is stimulated by the nostrils and at the back of the throat (eating/drinking molecules travel up the throat to receptors in back of the nose). The olfactory system links smells to emotions and memories (connecting directly to the limbic system and cerebral cortex), influencing behaviors and communication (feeding, self-defense, social interaction, reproduction), and alerting us to danger (gas leaks, spoiled food, fire). Also see Sensory System