Chemoreceptor

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chemoreceptor

[‚kē·mō·ri′sep·tər]
(physiology)
Any sense organ that responds to chemical stimuli.

Chemoreceptor

 

a specialized sensory cell or cellular structure, for example, a nerve ending, by which animals and humans perceive chemical stimuli, including metabolic changes. The effect of chemical agents on the receptors, like that of other stimuli on the corresponding receptor cells, gives rise to bioelectric potentials in the chemoreceptors and related nerve cells. Some chemoreceptors are highly selective, reacting only to a single substance or to a small group of substances; examples are the chemoreceptors in insects that are sensitive to pheromenes or receptors that react to carbon dioxide.

External (sensory) chemoreceptors signal fluctuations in the pH and ion composition of water and in the composition of atmospheric gases. They also indicate the presence in the environment or oral cavity of nutrients, caustic or toxic substances, and special chemical signals exchanged between living organisms. Internal chemoreceptors, which are a type of interoceptor, are sensitive to the chemical constituents of blood and other internal fluids.

From the evolutionary standpoint, chemoreceptors are probably the most ancient receptor formations. The sensory chemoreceptors of vertebrates include the olfactory and gustatory cells situated in the organs of smell and taste, as well as the free nerve endings in the skin that perform the function of “general chemical sensation.” Olfactory and gustatory chemoreceptors are also distinguished on the basis of functional and morphological characteristics in some invertebrates, for example, insects. However, this distinction cannot always be made in the case of invertebrates, especially aquatic forms.

In molecular biology, the term “chemoreceptor” is also used to designate a subcellular formation, that is, a specialized macromolecular structure arranged on the external surface of the cell membrane, that interacts with the molecules of chemical stimuli. The term is also used to designate similar receptors in protozoans.

A. V. MINOR

References in periodicals archive ?
2] causes a ventilatory response primarily through the central chemoreceptors (approximately 80 percent) with the remainder attributable to the peripheral chemoreceptors.
Bauer (2004) stated that the antennal flagella of carideans have abundant tactile and chemoreceptors, especially for gustation.
Contribution of baroreceptors and chemoreceptors to ventricular hypertrophy produced by sino-aortic denervation in rats.
Chemosensory protein in antenna of ant males plays an important role in receptors and communication needs whereas it was described as chemoreceptors [5] Sensilla were surrounded by highly concentrated olfactory proteins in the sensilla lymph, whereas these small amphipathic proteins serve as carriers to transport the hydrophobic molecules across the aqueous sensillar lymph to reach the olfactory receptors [7].
Tarsal chemoreceptors may respond to vapours and the most noticeable effect of repellent vapours on flight posture of Ae.
The cardiovascular response to hypoxia is to increase cardiac output; heart rate increases due to the reflex responses of carotid and aortic chemoreceptors as well (1).
Bees do not have ears, but they have an excellent sense of smell with chemoreceptors in their antennae.
Whelks appear to have broadly tuned chemoreceptors and manufactured baits may need to mimic the complex mixture of odorants derived from natural sources.
com/ The second company in the new generation of XL TechGroup businesses is: - TyraTech LLC, which was created by XL TechGroup in July 2004, is developing a new class of highly effective, non-toxic pesticides using cloned insect chemoreceptors, based on approved, safe, natural oils.
We investigated chemosensory behavior of the crayfish Procambarus clarkii in response to glutamate and glucose (not stimulatory to leg chemoreceptors in physiological tests), ammonium, glycine, maltose, and trehalose (known physiological stimuli), and a blank.
Steffensen (1985) suggested possible involvement of both chemoreceptors and mechanoreceptors in the mode-switching reflex.
Nicotine also stimulates chemoreceptors of the carotid and aortic body and causes release of catecholamines and further vasoconstriction.