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Aortic bodies

Chemoreceptors. The peripheral chemoreceptors include the carotid bodies, located at the bifurcation of the common carotid arteries, and the aortic bodies, located in the aortic arch. These receptors are stimulated by a decrease in arterial oxygen (hypoxia), an increase in arterial carbon dioxide (hypercapnia),... [Pg.207]

The peripheral chemoreceptors include the carotid and aortic bodies. The carotid bodies, which are more important in humans, are located near the bifurcation of the common carotid arteries. The aortic bodies are located in the arch of the aorta. The peripheral chemoreceptors respond to a decrease in P02/ an increase in PC02, and a decrease in pH (increase in H+ ion concentration) of the arterial blood. [Pg.273]

A2A receptors that are present on sensory nerves in the carotid body, aortic body and elsewhere in the periphery produce excitatory sensory input. These receptors have been implicated in the production of pain associated with angina pectoris, ulcer and the human blister base preparation. [Pg.314]

HCN is a systemic poison toxicity is due to inhibition of cytochrome oxidase, which prevents cellular utilization of oxygen. Inhibition of the terminal step of electron transport in cells of the brain results in loss of consciousness, respiratory arrest, and ultimately, death. Stimulation of the chemoreceptors of the carotid and aortic bodies produces a brief period of hyperpnea cardiac irregularities may also occur. The biochemical mechanisms of cyanide action are the same for all mammalian species. HCN is metabolized by the enzyme rhodanese which catalyzes the transfer of sulfur from thiosulfate to cyanide to yield the relatively nontoxic thiocyanate. [Pg.229]

In addition to binding to cytochrome c oxidase, cyanide inhibits catalase, peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, and succinic dehydrogenase activities. These reactions may make contributions to the signs of cyanide toxicity (Ardelt et al. 1989 Rieders 1971). Signs of cyanide intoxication include an initial hyperpnea followed by dyspnea and then convulsions (Rieders 1971 Way 1984). These effects are due to initial stimulation of carotid and aortic bodies and effects on the central nervous system. Death is caused by respiratory collapse resulting from central nervous system toxicity. [Pg.96]

Neuronal nicotinic receptors are present on sensory nerve endings—especially afferent nerves in coronary arteries and the carotid and aortic bodies as well as on the glomus cells of the latter. Activation of these receptors by nicotinic stimulants and of muscarinic receptors on glomus cells by muscarinic stimulants elicits complex medullary responses, including respiratory alterations and vagal discharge. [Pg.139]

Q5 Alkalosis can be caused by both metabolic and respiratory problems. Apart from hyperventilation, respiratory alkalosis can be produced by hypoxia, for example, when a person moves to high altitude with a reduced arterial P02, stimulation of respiration occurs via the peripheral chemoreceptors in the carotid and aortic bodies, which respond to the low arterial P02. Increased rate and depth of respiration causes an increased quantity of C02 to be lost from the body, and so pH rises. [Pg.188]

Doses from/with smoking. Nicotine causes release of catecholamines in the CNS, also serotonin, and antidiuretic hormone, corticotrophin and growth hormone. The effects of nicotine on viscera are probably largely reflex, from stimulation of sensory receptors (chemoreceptors) in the carotid and aortic bodies, pulmonary circulation and left ventricle. Some of the results are mutually antagonistic. [Pg.175]

Olson JL, Salyer WR. Mediastinal paraganglioma (aortic body tumor) A report of four cases, and a review of the literature. Cancer. 1978 41 2405-2412. [Pg.367]

Chemoreceptors. Early investigators assumed that the chemically sensitive areas controlling respiration were located in the brain. In 1926 De Castro (15) suggested that the carotid bodies, located near the carotid bifurcation of each common carotid artery, also could be important chemoreceptors. Shortly thereafter, Heymans and Heymans (16) found that ventilation was stimulated when the aortic arch of an animal was perfused with blood from an animal breathing a low oxygen air mixture. This study established the existence and general location of chemosensi-tive bodies in the aortic arch (the aortic bodies). Additional studies by Heymans and co-workers (17) delineated the location and function of the carotid bodies and demonstrated that they were stimulated by hypoxia and hypercapnia. The exact location and function of the aortic bodies was described by Comroe (18). [Pg.279]

In general, these findings added a new dimension to the understanding of respiratory regulation and provided a basis for later studies which more clearly established the physiological role of the aortic and carotid bodies and the magnitude and nature of the effects of chemical stimuli. Most of these studies have been concerned with the carotid bodies since they can be isolated and perfused their innervation in animals is readily accessible for recording with electrodes. The aortic bodies are fairly inaccessible, and much of the evidence for their function is indirect (3). [Pg.279]

The chemosensitive cells of carotid and aortic bodies (the peripheral chemoreceptors) are stimulated by decreases in the 02 tension of arterial blood perfusing the peripheral chemoreceptors and by increases in arterial pCo2 or arterial [H+]. The stimulation resulting from increased arterial pco2 Is probably an indirect result of increased [H+] from the acidifying action of C02 in the vicinity of the chemosensitive cells. It now seems that these bodies respond to changes in their extracellular [H+] and can respond to even the most acute metabolic acid-base disturbance without significant delay (19). [Pg.279]

The influence of ACh and parasympathetic innervation on various organs and tissues is discussed in detail in Chapter 6. ACh and its analogs stimulate secretion by all glands that receive parasympathetic innervation, including the lacrimal, tracheobronchial, salivary, and digestive glands. The effects on the respiratory system, in addition to increased tracheobronchial secretion, include hronchoconstriction and stimulation of the chemoreceptors of the carotid and aortic bodies. When instilled into the eye, muscarinic agonists produce miosis (see Chapter 63). [Pg.115]

As for adrenaline at least, an interruption on the entire respiratory metabolism may be observed, which is reflected on the chemoceptors of the carotid body by the variations of oxygen uptake and carbon dioxide production (148). The direct intervention on the chemoceptors of the carotid and aortic bodies only appears for the nicotinic substances and not for Pervitin (149). The natural sympathomimetics which possess a stimulating influence on the respiration are mainly ephedrine, hordenine, 0-phenylethylamine, and tyramine. [Pg.128]

The Zuckerkandl organs arc para-aortic bodies of chromaffin tissue, which arc located retroperitoneally at the, level of the origin of the inferior mesenteric artery. These organs function as an accessory tissue to the autonomic nervous system in early life they usually start to degenerate during the first postnatal year. [Pg.126]

The two major peripheral chemoreceptors are the carotid and the aortic bodies. The central chemoreceptors are probably localized close to the respiratory center in the medulla. [Pg.579]

Between 1927 and 1930, Heymans discovered the chemoreceptor reflexes in the carotid and aortic bodies. He showed that when stimulated, these receptors excite the respiratory center. [Pg.579]

The aortic body s structure resembles that of the carotid body. The aortic body is at the root of the right subclavian artery and scattered around the transverse part of the aortic arch. [Pg.580]

The following are rare sites for these tumours the pleural cavity, the splenic hilum, the renal hilum, the adnexa, " the bladder, " 1507-16) carotid and aortic bodies. " The occurrence of several... [Pg.92]

For a long time, lobeiine was known as a powerful respiratory stimulant. This important property has been explained by the activation of the carotid and aortic body chemoreceptors at therapeutic doses. [Pg.332]

The fetus is living at low PO2 Mount Everest in utero and is at birth suddenly exposed to high PO2. This transition requires a change of setting of oxygen sensitivity. The carotid and aortic bodies are the main peripheral O2 sensors. While the carotid bodies seem to be the main peripheral chemoreceptors involved in respiratory control, the aortic bodies are more involved in cardiovascular homeostasis in the fetus (1). They have a low hypoxic sensitivity and their involvement in the hypoxic ventilatory response is controversial (2). [Pg.235]

To put the problem in the simplest way is to consider the carotid bodies (as well as the aortic bodies) either as simple receptors, in which sensory nerve terminals are directly excited by the chemical stimuli carried by the blood, or as composite receptors, in which chemical stimuli only reach and act upon... [Pg.353]

Coleridge HM, Coleridge JC, Howe A. A search for puhnonaty arterial chemoreceptors in the cat, with a comparison of the blood supply of the aortic bodies in the newborn and adult animal. J Physiol (Lond) 1967 191 353-374. [Pg.361]

Figure 1 Schematic diagram to illustrate the distribution of 02-sensitive chemoreceptors in different vertebrate groups. VII, IX, and X refer to cranial nerves (facial, glossopharyngeal, and vagus nerves) while 2, 3, 4, 5, and 6 refer to arteries supplying the respective embryonic gill arches. While O2 chemoreceptors are found in the aortic bodies of mammals, they do not appear to serve a respiratory role. See text for further details. Figure 1 Schematic diagram to illustrate the distribution of 02-sensitive chemoreceptors in different vertebrate groups. VII, IX, and X refer to cranial nerves (facial, glossopharyngeal, and vagus nerves) while 2, 3, 4, 5, and 6 refer to arteries supplying the respective embryonic gill arches. While O2 chemoreceptors are found in the aortic bodies of mammals, they do not appear to serve a respiratory role. See text for further details.
In mammals the carotid bodies are situated at the bifurcations of the cormnon carotid arteries into their internal and external branches and are irmervated by the sinus nerve, a branch of cranial nerve EX (Fig. 1). The aortic bodies in mammals, on the other hand, are located in the region of the aortic arch and the roots of the major arteries of the thorax. Their afferent fibers nm in the aortic nerve, a branch of the vagus (Fig. 1). They appear to make little contribution to the resting ventilatory drive in eucapnic normoxia and may not contribute to the hypoxic ventilatory response in many species. It would appear that they participate almost exclusively in cardiovascular reflexes in this group (see Ref. 25 for review). Glomus tissue that may... [Pg.687]

Lahiri S, Milligan E, Nishino T, Mokashi A, Davies RO. Relative responses of aortic body and carotid body chemoreceptors to carboxhemoglobinemia. J Appl Physiol 1981 50 580-586. [Pg.704]


See other pages where Aortic bodies is mentioned: [Pg.208]    [Pg.258]    [Pg.397]    [Pg.231]    [Pg.495]    [Pg.495]    [Pg.144]    [Pg.144]    [Pg.856]    [Pg.581]    [Pg.120]    [Pg.274]    [Pg.692]    [Pg.693]   
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