Chemical senses


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Chemical senses

In vertebrates, the senses of smell (olfaction) and taste (gustation) plus the so-called common chemical sense constitute the external chemical senses (as contrasted with internal chemoreceptors). The olfactory cells of vertebrates, usually located in the olfactory mucosa of the upper nasal passages, are specialized neural elements that are responsive to chemicals in the vapor phase. Taste buds of the oral cavity, especially the tongue, are composed of modified epithelial cells responsive to chemicals in solution. The common chemical senses are composed of free nerve endings in the mucous membrane of the eye, nose, mouth, and digestive tract and are responsive to irritants or other chemicals in either the vapor or liquid phase. See Chemoreception

Among invertebrates, sense organs occur as specialized hairs and sensilla, or minute cones supplied with sensory nerves and nerve cells. Characteristic of male moths, for example, are their distinctive bushy antennae, by which they detect and locate females by sex pheromones. Rodents, ungulates, carnivores, and other mammals also show sexual attraction to female odors produced by specialized glands. Whether humans in general are susceptible to pheromonal influences from other humans is debatable. See Pheromone

Taste plays an important role in selection and acceptance of food. Besides the protective, inborn aversion to bitter (many poisons, but not all, are bitter), a single experience with the particular taste of a toxic substance which caused illness may establish a strong and persistent learned taste aversion. By contrast, a compensatory salt hunger may occur in persons or animals suffering salt deficiency.

The limbic system of the brain, which modulates appetitive and emotional behavior and hedonic (pleasant vs. unpleasant) experiences, has both taste and olfactory neural pathways to it, providing the neural substrate for the pleasure or displeasure of sensations. See Neurobiology, Olfaction, Sensation, Taste

References in periodicals archive ?
Wysocki, Monell Chemical Senses Center, Philadelphia, PA.
Remarkable progress has been made in establishing the nature of changes that occur in the chemical senses with age.
Researchers at the Moneli Chemical Senses Center in Philadelphia, as reported in American Journal of Clinical Nutrition, put a college students on a diet extremely low in sodium and, to make matters worse, then gave them diuretics.
Pamela Dalton is an olfactory (smell sense) scientist with the Monell Chemical Senses Center in Philadelphia.
Danielle Dixson, an assistant professor in the School of Biology at the Georgia Institute of Technology in Atlanta, said there's no difference between the fish treated with CO2 in the lab in tests for chemical senses versus the fish they caught and tested from the CO2 reef.
Dr Charles Wysocki, PhD, a behavioural neuroscientist at Monell Chemical Senses Centre in Philadelphia carried out the study.
Charles Wysocki of the Monell Chemical Senses centre in Philadelphia, USA, said: "It is quite difficult to block a woman's awareness of body odour.
Our findings may some day allow doctors to screen for and diagnose skin cancers at very early stages," said study leader Dr Michelle Gallagher, from the Monell Chemical Senses Centre in Philadelphia, US.
The Monell Chemical Senses Center, a nonprofit research institute focused on taste and smell, has surpassed its goal in its first ever capital campaign.
Researchers at the Monell Chemical Senses Center, a nonprofit research institute based in Philadelphia, Pennsylvania, have discovered a genetic flaw in cats that any human who battles the bulge would like to have--a dysfunctional gene that prevents them from detecting sweets.
Scientists at the Monell Chemical Senses Center in Philadelphia report that genes might play a large role in determining individual differences in sour taste perception.
Joe Brand, a biophysicist at the Monell Chemical Senses Center in Philadelphia, and colleagues analyzed the genes that make cats' sweet-detecting receptors.

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