Retronasal smell

Human olfactory system. 1

Retronasal smell refers to the perception of odors through the mouth while eating and drinking. Unlike orthonasal olfaction, which involves the detection of odors through the nostrils, retronasal smell occurs when the olfactory stimuli reach the olfactory epithelium in the back of the nasal cavity via the pharynx. This process is essential for the perception of flavor, as it combines with taste and other sensory inputs to form the overall flavor experience of food and beverages.

Mechanism

The mechanism of retronasal smell begins when food is chewed and mixed with saliva, releasing volatile compounds. As one swallows, the volatile molecules are pushed upwards into the nasal cavity through the pharynx. This backward movement allows the molecules to come into contact with the olfactory receptors located on the olfactory epithelium. The signals from these receptors are then transmitted to the brain, where they are interpreted as flavors.

Importance in Flavor Perception

Retronasal smell plays a crucial role in the perception of flavor. It is responsible for the complexity and richness of flavors that cannot be detected through taste alone. Taste, which is limited to sweet, sour, salty, bitter, and umami, is significantly enhanced by the aromas detected through retronasal olfaction. This is why food may appear tasteless when one has a blocked nose or a condition that affects the sense of smell.

Differences Between Retronasal and Orthonasal Smell

While both retronasal and orthonasal smell involve the detection of odors, they differ in the path the odors take to reach the olfactory epithelium. Orthonasal smell occurs when odors enter the nostrils from the external environment, whereas retronasal smell involves the passage of odors from the mouth to the nasal cavity. This difference in pathway results in distinct sensory experiences, with retronasal smell being more closely linked to the perception of flavor.

Research and Applications

Research in the field of retronasal smell has significant implications for the food and beverage industry, as well as for health and nutrition. Understanding how retronasal olfaction contributes to flavor perception can aid in the development of more flavorful and appealing food products. Additionally, studying the impact of various factors, such as age or disease, on retronasal smell can provide insights into improving the eating experience for individuals with diminished olfactory function.

See Also

• Olfaction
• Taste
• Flavor
• Olfactory system

This sensory-related article is a stub. You can help WikiMD by expanding it.