Olfactory System
The parts of the body involved in sensing smell, including the nose and many parts of the brain. Smell may affect emotion, behavior, memory, and thought.
How the Sense of Smell Works
Your sense of smell – like your sense of taste – is part of your chemosensory system, or the chemical senses.
Your ability to smell comes from specialized sensory cells, called olfactory sensory neurons, which are found in a small patch of tissue high inside the nose. These cells connect directly to the brain.
Each olfactory neuron has one odor receptor. Microscopic molecules released by substances around us—whether it’s coffee brewing or pine trees in a forest—stimulate these receptors.
Once the neurons detect the molecules, they send messages to your brain, which identifies the smell. There are more smells in the environment than there are receptors, and any given molecule may stimulate a combination of receptors, creating a unique representation in the brain. These representations are registered by the brain as a particular smell.
Smells reach the olfactory sensory neurons through two pathways. The first pathway is through your nostrils.
The second pathway is through a channel that connects the roof of the throat to the nose. Chewing food releases aromas that access the olfactory sensory neurons through the second channel. If the channel is blocked, such as when your nose is stuffed up by a cold or flu, odors can’t reach the sensory cells that are stimulated by smells. As a result, you lose much of your ability to enjoy a food’s flavor. In this way, your senses of smell and taste work closely together…Read more about Smell and Smell Disorders NIH – National Institute on Deafness and Other Communication Disorders
