Chemoreceptor

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chemoreceptor

[‚kē·mō·ri′sep·tər]
(physiology)
Any sense organ that responds to chemical stimuli.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The effect of blood pressure upon chemoreceptor discharge to hypoxia, and the modification of this effect by the sympathetic-adrenal system.
Antagonistic frequency tuning of hair bundles by different chemoreceptors regulates nematocyst discharge.
(1994) Carotid body chemoreceptors: from natural stimuli to sensory discharges.
In many lepidopteran larvae, the chemosensilla or chemoreceptors present on galea, maxillary palp, and the inner surface of the labrum are involved in determining food preferences (Ishikawa 1963; Ma 1972; Dethier 1973; Stadler & Hanson 1975; De Boer et al.
Anker et al., "Peripheral chemoreceptor hypersensitivity: an ominous sign in patients with chronic heart failure," Circulation, vol.
But the peripheral chemoreceptors respond more rapidly to decreased or increased arterial oxygen partial pressure (PaO2), decreased or increased PaCO2, and increased or decreased arterial pH because there are no barriers at all to pass.
Cardiovascular adjustments induced by hypertonic saline in hemorrhagic rats: Involvement of carotid body chemoreceptors. Auton Neurosci 2011; 160: 37-41, doi: 10.1016/j.autneu.2010.11.009.
This stimulation of the peripheral chemoreceptors induces an increase in the activity of the autonomous sympathetic nervous system (ANS) and in the production on catecholamine.
Beneficial effects of oxygen could be related to changes in chemoreceptor stimulation, changes in breathing pattern, and/or stimulation of receptors related to gas flow through the upper airway.
in the anterior areas may act as tango-receptors or chemoreceptors. The dome-shaped structures may be concerned with the control of the attachment and detachment mechanism of the anterior adhesive sacs to help in maintenance of the parasite's adhesive attitude between gills.
These structures are cuticular extensions, with shafts of different shapes and sizes, that can function as mechanoreceptors and/or chemoreceptors. Most are bimodal mechanoreceptors-chemoreceptors, combining the anatomic characteristics and functions of the 2 types.
During wakefulness, the body responds to hypoxia and hypercapnia via peripheral chemoreceptors that communicate with the brain to initiate a breath.