Also found in: Dictionary, Thesaurus, Medical, Wikipedia.


Any sense organ that responds to chemical stimuli.



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.


References in periodicals archive ?
These changes during sleep onset might actually reflect the reactivation of the chemoreceptor system, which is pre-empted during wakefulness by the wakefulness drive.
The most important or dominant sensors for the control of breathing or respiratory drive are the central chemoreceptors in the medulla of the brain, and peripheral chemoreceptors in the carotid and aortic bodies in the arterial blood system.
On the other hand, in contrast to aortic denervation, sino-aortic denervation, as usually performed, also destroys carotid chemoreceptors and results in hypoventilation, which by itself induces chronic hypoxia with its consequent chronic lowering of blood pressure (22,23).
Antennae are the major site of the chemoreceptors that detect and discriminate between air-borne stimuli and guide the mosquitoes to suitable human host or to an oviposition site.
Whelks appear to have broadly tuned chemoreceptors and manufactured baits may need to mimic the complex mixture of odorants derived from natural sources.
Haloperidol is the most potent dopamine-2 antagonist at the chemoreceptor trigger zone.
3] receptors located on peripheral vagal nerve terminals and centrally in the chemoreceptor trigger zone, resulting in the initiation of the vomiting reflex.
The urge to vomit comes from two areas in the brain - a vomiting centre set off by a chemoreceptor trigger zone, which rings when you've been boozing too much.
Phenothiazines, butyrophenones, and metoclopramide (Reglan) have the most direct effect on blocking the pathway between the center in the medulla that controls vomiting and the chemoreceptor trigger.
The basis for separating them into classes is determined by the presence or absence of a phasmid, a small sensory organ, probably a chemoreceptor located on the suffice of the nematode.
Electrical engineers are currently developing computerized chemoreceptor devices that take air samples to detect the airborne molecules which currently only dogs can smell.
The bacteria with no flagella destroy their chemoreceptor proteins.