Odor

Odor or odour refers to the characteristic smell given off by different substances. The perception of odor, known as Olfaction, is a complex process that involves the sensory system and the brain. Odors can be pleasant, such as the smell of fresh flowers, or unpleasant, like the smell of rotten food.

Causes of Odor

Odors are caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of Olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors.

Perception of Odor

The perception of odors, or sense of smell, is mediated by the Olfactory system. The olfactory system is often spoken of along with the Gustatory system as the chemosensory senses because both transduce chemical signals into perception.

Odor Molecules

Odor molecules are typically light, volatile (easily vaporized) chemicals that float through the air into your nose. Once inside, they are detected by various types of sensory neurons that are specialized to detect specific types of molecules.

Odor Intensity

Odor intensity can be expressed using an odor concentration or an odor detection threshold. Odor concentration is the amount of odorant air. As odor sensation usually depends on the concentration available at the receptor site, odor intensity depends on the number of receptors activated.

Odor and Taste

Odor is a significant contributor to the sense of taste. While the tongue can only sense five basic tastes, the nose can sense a virtually unlimited number of smells. This combination of taste and smell is what makes the perception of flavor.

See Also

• Olfaction
• Olfactory system
• Gustatory system

Odor Resources
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