Role of peripheral chemoreceptors and central chemosensitivity in the regulation of respiration and circulation.

1982 ◽  
Vol 100 (1) ◽  
pp. 23-40 ◽  
Author(s):  
R G O'Regan ◽  
S Majcherczyk
Keyword(s):  
The Body ◽  
Ion Concentration ◽  
Regulation Of Respiration ◽  
Acid Base Balance ◽  
Acid Base ◽  
Vascular Effects ◽  
Peripheral Chemoreceptor ◽  
Hydrogen Ion Concentration ◽  
Central Chemosensitivity ◽  
Base Balance

Adjustments of respiration and circulation in response to alterations in the levels of oxygen, carbon dioxide and hydrogen ions in the body fluids are mediated by two distinct chemoreceptive elements, situated peripherally and centrally. The peripheral arterial chemoreceptors, located in the carotid and aortic bodies, are supplied with sensory fibres coursing in the sinus and aortic nerves, and also receive sympathetic and parasympathetic motor innervations. The carotid receptors, and some aortic receptors, are essential for the immediate ventilatory and arterial pressure increases during acute hypoxic hypoxaemia, and also make an important contribution to respiratory compensation for acute disturbances of acid-base balance. The vascular effects of peripheral chemoreceptor stimulation include coronary vasodilation and vasoconstriction in skeletal muscle and the splanchnic area. The bradycardia and peripheral vasoconstriction during carotid chemoreceptor stimulation can be lessened or reversed by effects arising from a concurrent hyperpnoea. Central chemoreceptive elements respond to changes in the hydrogen ion concentration in the interstitial fluid in the brain, and are chiefly responsible for ventilatory and circulatory adjustments during hypercapnia and chronic disturbances of acid-base balance. The proposal that the neurones responsible for central chemoreception are located superficially in the ventrolateral portion of the medulla oblongata is not universally accepted, mainly because of a lack of convincing morphological and electrophysiological evidence. Central chemosensitive structures can modify peripheral chemoreceptor responses by altering discharges in parasympathetic and sympathetic nerves supplying these receptors, and such modifications could be a factor contributing to ventilatory unresponsiveness in mild hypoxia. Conversely, peripheral chemoreceptor drive can modulate central chemosensitivity during hypercapnia.

Disorders of acid–base balance

2018 ◽  
Author(s):  
Aron Chakera ◽  
William G. Herrington ◽  
Christopher A. O’Callaghan
Keyword(s):  
The Body ◽  
Ion Concentration ◽  
Acid Base Balance ◽  
Acid Base ◽  
Compensatory Mechanisms ◽  
Urine Ph ◽  
Hydrogen Ion Concentration ◽  
Normal Metabolism ◽  
Base Balance ◽  
Ph Scale

Normal metabolism results in a net acid production of approximately 1 mmol/kg day−1. Physiological pH is regulated by excretion of this acid load (as carbon dioxide) by the kidneys and the lungs. A series of buffers in the body reduces the effects of metabolic acids on body and urine pH. For acid–base disorders to occur, there must be excessive intake (or loss) of acid (or base) or, alternatively, an inability to excrete acid. For these changes to result in a substantially abnormal pH, the various buffer systems must been overwhelmed. The pH scale is logarithmic, so relatively small changes in pH signify large differences in hydrogen ion concentration. Most minor perturbations in acid–base balance are asymptomatic, as small changes in acid or base levels are rapidly controlled through consumption of buffers or through changes in respiratory rate. Alterations in renal acid excretion take some time to occur. Only when these compensatory mechanisms are overwhelmed do symptoms related to changes in pH develop. This chapter reviews the causes and consequences of acid–base disorders.

The highs and lows of electrolytes part 2: calcium, phosphate and magnesium

2021 ◽  
Vol 12 (1) ◽  
pp. 20-25
Author(s):  
Paula Anderson
Keyword(s):  
Critical Care ◽  
Calcium Phosphate ◽  
The Body ◽  
Cellular Functions ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Critical Care Patients

There are six electrolytes that are important in maintaining homeostasis within the body. They play vital roles in regulating neurological, myocardial, muscular and cellular functions and are involved in fluid and acid–base balance. Recognising and treating electrolyte derangements is an important role for veterinary nurses especially in emergency and critical care patients. This series of two articles will discuss the physiology behind each of the six major electrolytes and discuss to monitor and treat any abnormalities.

Physicochemical analysis of phasic menstrual cycle effects on acid-base balance

2001 ◽  
Vol 280 (2) ◽  
pp. R481-R487 ◽  
Author(s):  
Robert J. Preston ◽  
Aaron P. Heenan ◽  
Larry A. Wolfe
Keyword(s):  
Menstrual Cycle ◽  
Ventilatory Threshold ◽  
Physicochemical Analysis ◽  
Carbon Dioxide Tension ◽  
Weak Acid ◽  
Ion Concentration ◽  
Strong Ion Difference ◽  
Acid Base Balance ◽  
Hydrogen Ion Concentration ◽  
Base Balance

In accordance with Stewart's physicochemical approach, the three independent determinants of plasma hydrogen ion concentration ([H+]) were measured at rest and during exercise in the follicular (FP) and luteal phase (LP) of the human menstrual cycle. Healthy, physically active women with similar physical characteristics were tested during either the FP ( n = 14) or LP ( n = 14). Arterialized blood samples were obtained at rest and after 5 min of upright cycling at both 70 and 110% of the ventilatory threshold (TVent). Measurements included plasma [H+], arterial carbon dioxide tension (PaCO2 ), total weak acid ([ATot]) as reflected by total protein, and the strong-ion difference ([SID]). The transition from rest to exercise in both groups resulted in a significant increase in [H+] at 70% TVentversus rest and at 110% TVent versus both rest and 70% TVent. No significant between-group differences were observed for [H+] at rest or in response to exercise. At rest in the LP, [ATot] and PaCO2 were significantly lower (acts to decrease [H+]) compared with the FP. This effect was offset by a reduction in [SID] (acts to increase [H+]). After the transition from rest to exercise, significantly lower [ATot] during the LP was again observed. Although the [SID] and PaCO2 were not significantly different between groups, trends for changes in these two variables were similar to changes in the resting state. In conclusion, mechanisms regulating [H+] exhibit phase-related differences to ensure [H+] is relatively constant regardless of progesterone-mediated ventilatory changes during the LP.

Acid-Base Balance with Different Capd Solutions

1996 ◽  
Vol 16 (1_suppl) ◽  
pp. 126-129 ◽  
Author(s):  
Mariano Feriani ◽  
Claudio Ronco ◽  
Giuseppe La Greca
Keyword(s):  
Acid Production ◽  
Dwell Time ◽  
Lactate Concentration ◽  
The Body ◽  
Plasma Lactate ◽  
Acid Base Balance ◽  
Bicarbonate Concentration ◽  
Acid Base ◽  
Plasma Bicarbonate ◽  
Base Balance

Our objective is to investigate transperitoneal buffer fluxes with solution containing lactate and bicarbonate, and to compare the final effect on body base balance of the two solutions. One hundred and four exchanges, using different dwell times, were performed in 52 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Dialysate effluent lactate and bicarbonate and volumes were measured. Net dialytic base gain was calculated. Patients’ acid-base status and plasma lactate were determined. In lactate-buffered CAPD solution, lactate concentration in dialysate effluent inversely correlated with length of dwell time, but did not correlate with plasma lactate concentration and net ultrafiltration. Bicarbonate concentration in dialysate effluent correlated with plasma bicarbonate and dwell time but not with ultrafiltration. The arithmetic sum of the lactate gain and bicarbonate loss yielded the net dialytic base gain. Ultrafiltration was the most important factor affecting net dialytic base gain. A previous study demonstrated that in patients using a bicarbonate-buffered solution the net bicarbonate gain is a function of dwell time, ultrafiltration, and plasma bicarbonate. By combining the predicted data of the dialytic base gain with the calculated metabolic acid production, an approximate body base balance could be obtained with both lactate and bicarbonate-buffered CAPD solutions. The body base balance in CAPD patients is self-regulated by the feedback between plasma bicarbonate concentration and dialytic base gain. The level of plasma bicarbonate is determined by the dialytic base gain and the metabolic acid production. This can explain the large interpatient variability in acid-base correction. Bicarbonate-buffered CAPD solution is equal to lactate solution in correcting acid-base disorders of CAPD patients.

scholarly journals Effect of Simulated Matches on Post-Exercise Biochemical Parameters in Women’s Indoor and Beach Handball

2020 ◽  
Vol 17 (14) ◽  
pp. 5046
Author(s):  
Joanna Kamińska ◽  
Tomasz Podgórski ◽  
Jakub Kryściak ◽  
Maciej Pawlak
Keyword(s):  
Blood Parameters ◽  
Ion Concentration ◽  
Electrolyte Balance ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Physically Active ◽  
Post Exercise ◽  
Before And After ◽  
Base Balance

This study assesses the status of hydration and the acid-base balance in female handball players in the Polish Second League before and after simulated matches in both indoor (hall) and beach (outdoor) conditions. The values of biochemical indicators useful for describing water-electrolyte management, such as osmolality, hematocrit, aldosterone, sodium, potassium, calcium, chloride and magnesium, were determined in the players’ fingertip capillary blood. Furthermore, the blood parameters of the acid-base balance were analysed, including pH, standard base excess, lactate and bicarbonate ion concentration. Additionally, the pH and specific gravity of the players’ urine were determined. The level of significance was set at p < 0.05. It was found that both indoor and beach simulated matches caused post-exercise changes in the biochemical profiles of the players’ blood and urine in terms of water-electrolyte and acid-base balance. Interestingly, the location of a simulated match (indoors vs. beach) had a statistically significant effect on only two of the parameters measured post-exercise: concentration of calcium ions (lower indoors) and urine pH (lower on the beach). A single simulated game, regardless of its location, directly affected the acid-base balance and, to a smaller extent, the water-electrolyte balance, depending mostly on the time spent physically active during the match.

Suprapontine mechanisms in regulation of respiration

1962 ◽  
Vol 202 (2) ◽  
pp. 217-220 ◽  
Author(s):  
B. R. Fink ◽  
R. Katz ◽  
H. Reinhold ◽  
A. Schoolman
Keyword(s):  
Brain Stem ◽  
Ventilatory Response ◽  
Regulation Of Respiration ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Reticular Activating System ◽  
The Brain ◽  
Frequency Of Respiration

The ventilation and blood acid-base balance of 19 cats were studied after supracollicular ablation of the forebrain and again after intercollicular transection of the brain stem. The first ablation caused a marked increase in the frequency of respiration, apparently unmasking a caudad facilitory influence through the removal of forebrain inhibition. Hypocapnic apnea could not be induced in this preparation. After intercollicular section there was a sudden fall in frequency, the ventilatory response to CO2 was diminished and hypocapnic apnea was easily induced. It is concluded that a tonic facilitory effect on respiration originates in the rostral midbrain and adjacent diencephalon, possibly in the reticular activating system.

ACID-BASE LANGUAGE VERSUS ACID-BASE MEASUREMENTS

PEDIATRICS ◽  
1969 ◽  
Vol 43 (5) ◽  
pp. 830-832
Author(s):  
Giles F. Filley
Keyword(s):  
The Body ◽  
Ion Concentration ◽  
Volatile Acid ◽  
Acid Base ◽  
Hydrogen Ion Concentration ◽  
Base Language ◽  
Physicochemical System ◽  
American Schools ◽  
Anglo American

The PAPERS of Kildeberg and Engel and of Nelson and Riegel continue what has been called, inaccurately, "The Great Transatlantic Acid-Base Debate" betsveen two schools of acid-base physiology. Historically at least, these can be called the Continental and Anglo-American Schools and their current dispute a war of words. We will sketch their beginnings, describe some of their differences, and indicate the importance of the distinction between fundamental and derived measurement. The Continental School was probably founded by Hasselbalch, who in 1916 began the apparently never-ending search for a chemical index of a "metabolic component," i.e., a number indicating the quantity of non-volatile acid added to or lost from the body-"corrected" for respiratory effects. Hasselbalch index was typical of the genre because it required exposing a blood specimen in vitro to known CO2 gas mixtures and was called a "reduced hydrogen ion concentration." His successors have tended to work meticulously in chemical laboratories, to give special names to defined magnitudes, and to incorporate these into logical formulations. One example was that of Singer and Hastings, which was based on a thoroughgoing study of blood as a physicochemical system at various states of equilibrium outside the body. Another recent and carefully developed one is that of Siggaard-Andersen. Despite this and other authors warnings, this school formulations are subject to abuse perhaps especially by those who assume that an "Astrup determination" is a substitute for clinical judgement. The other school is less systematic, its members being more often physiologists or physicians than physical chemists.

Sign in / Sign up

Export Citation Format

Share Document