Acid-base balance regulation

Excretion into urine of ammonia produced by renal mbu-lar cells facilitates cation conservation and regulation of acid-base balance. Ammonia production from intracellular renal amino acids, especially glutamine, increases in metabolic acidosis and decreases in metabolic alkalosis. 

Hood FL, Tannen RL. Protection of acid-base balance by pH regulation of acid production. N Engl J Med 1998 339 819-826. 

Sometimes, the body needs some help regulating its acid-base balance. People who experience heartburn, for example, may resort to taking an antacid to neutralize the stomach acid creeping up their esophagus. One popular antacid, milk of magnesia, is actually magnesium hydroxide. The reaction between stomach acid and milk of magnesia is a neutralization reaction ... 

Obtains oxygen and eliminates carbon dioxide regulates acid-base balance (pH)... 

Acid-base balance involves chemical and physiological processes responsible for the maintenance of the pH of body fluids at levels that allow optimal function of the whole individual. The ability for the body to regulate pH is critically important in maintaining the operation of many cellular enzymes and the function of vital organs, such as the brain and the heart [143],... 

Kidney Failure, Chronic An irreversible and usually progressive reduction in renal function in which both kidneys have been damaged by a variety of diseases to the extent that they are unable to adequately remove the metabolic products from the blood and regulate the body s electrolyte composition and acid-base balance. Chronic kidney failure requires hemodialysis or surgery, usually kidney transplantation. [NIH]... 

Excess nitrogen is eliminated from the body in the urine. The kidney adds small quantities of ammonium ion to the urine in part to regulate acid-base balance, but nitrogen is also eliminated in this process. Most excess nitrogen is converted to urea in the liver and goes through the blood to the kidney, where it is eliminated in urine. 

Full details of the reaction are given in Appendix 8.4 and a detailed discussion of the role of the kidney in regulation of the acid/base balance is given in (Appendix 13.4). The oxoglutarate produced from these successive reactions is either oxidised to yield ATP or, under conditions of starvation, converted to glucose via gluconeogenesis (Figure 8.26). 

Homeostasis. The blood ensures that a balanced distribution of water is maintained between the vascular system, the cells (intracellular space), and the extracellular space. The acid-base balance is regulated by the blood in combination with the lungs, liver, and kidneys (see p. 288). The regulation of body temperature also depends on the controlled transport of heat by the blood. 

The kidneys main function is excretion of water and water-soluble substances (1). This is closely associated with their role in regulating the body s electrolyte and acid-base balance (homeostasis, 2 see pp.326 and 328). Both excretion and homeostasis are subject to hormonal control. The kidneys are also involved in synthesizing several hormones (3 see p. 315). Finally, the kidneys also play a role in the intermediary metabolism (4), particularly in amino acid degradation and gluconeo-genesis (see p. 154). 

The kidney regulates the acid-base balance of the body by control over resorption of sodium ions, which may exchange for hydrogen ions in the kidney tubule. Since most dietaries are of acid-ash, the urine is usually more acid than the original plasma filtrate and much of the phosphate excreted is thus changed to the acid monosodium salt, Within the range of normal variability, with an alkaline ash diet, the urine may become alkaline, and in extreme instances, some sodium bicarbonate may be excreted. 

The primary functions of the blood may be considered in a broad sense to be the following (1) metabolic regulation—transport of oxygen, carbon dioxide, metabolites, hormones (2) physical and chemical regulation—temperature, acid-base balance, and osmotic pressure and fluid balance and (3) regulation of body defenses—protection against infection by the action of antibodies, leukocytes, and other mechanisms and prevention of hemorrhage. 

Pitts, R.F. 1971. The role of ammonia production and excretion in regulation of acid-base balance. N. Engl. J. Med. 284(l) 32-38. 

Minerals include sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobalt and chlorine trace minerals include iron, zinc, copper, selenium, iodine, fluorine and chromium. Their roles may be generalised within the areas of providing structure in the formation of bones and teeth, maintenance of normal heart rhythm, muscle contractility, neural conductivity, acid-base balance and the regulation of cellular metabolism through their activ-ity/structural associations with enzymes and hormones. The daily requirements of minerals can be obtained from a well-balanced diet. 

Hanssinger, D. Liver regulation of acid-base balance. Min. Electr. Metab. 1997 23 249 -252... 

The protein and amino-acid metabolism of the liver is characterized by three essential functions (1.) production and breakdown of proteins, (2.) production and breakdown of amino acids as well as regulation of their concentrations in the blood, and (i.) detoxification of ammonium via the synthesis of urea (= excretory form) and glutamine (= non-toxic transport or storage form) with simultaneous regulation of the acid-base balance. The breakdown of branched-chain amino acids occurs only in the musculature by way of deamination, (s. pp 38, 43)... 

T he sea is a living system and, like other living systems, its properties are a complex fimction of many chemical and biological processes. Some of these involve, directly or indirectly, the protonation of basic species, and consequently the state of the seawater system— its equilibrium processes and the rate at which equilibrium is being approached —depends on pH. Interactions within the hydrosphere, in which carbonate, phosphate, and silicate play an important role, regulate the pH within rather narrow limits, as the acid-base balance of the human body controls the pH of human blood. 

The kidney is an organ that performs several important functions essential to sustain life. These functions include the regulation of volume and electrolyte homeostasis, control of acid-base balance, and the excretion of waste products. The kidney also has endocrine functions including renin secretion, stimulation of erythropoietin formation, and activation of vitamin D. Numerous disease states (e.g., infections, shock, diabetes, gout) can affect the ability of the kidney to perform its normal functions, and if these diseases are not properly treated, serious illness or death can result. 

The kidneys are critical organs. They filter wastes produced by metabolism from the blood and excrete them with water as urine. They are also major organs in whole body homeostasis, with acid-base balance, electrolyte concentration regulation, blood volume control, and blood pressure regulation functions. 

Factors that regulate distal tubular secretion of are intalce of Na" and K, plasma concentration of mineralocor-ticoids, and acid-base balance. Because renal conservation mechanisms are slow to respond, depletion can be an early consequence of restricted intake or losses of K by extrarenal routes. Diminished glomerular filtration rate is typical of renal failure, and the consequent decrease in distal tubular flow rate is an important factor in the retention of K seen in chronic renal failure. Renal tubular acidosis and metaboUc and respiratory acidoses and alkaloses also affect renal regulation of excretion. These topics are discussed in much greater detail in Chapters 45 and 46. 

Respiratory Mechanism in the Regulation of Acid-Base Balance... 

Oh MS, Carroll HJ. Regulation of intracellular and extracellular volume. In Arieff Al, DeFronzo RA, eds. Huid, Electrolyte, and Acid-Base Balance Disorders, 2nd ed. New York, Churchill Livingstone, 1995 1-28. 

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