Acid-base balance kidneys

Effects of repeated ethylene glycol peroral overexposure in treated rats and mice can result in kidney, Hver, and nervous system damage. The most sensitive indicators of ethylene glycol toxicity are disturbances in acid—base balance and nephrotoxic (kidney) effects. Effects of repeated chronic peroral overexposure of diethylene glycol in treated rats result in kidney and Hver damage (48). 

AQP6 is expressed in the intercalated cells of the kidney collecting duct. This channel is hardly permeable to water, but capable of transporting anions, including chloride, and is therefore thought to play a role in maintenance of body acid-base balance or in intracellular vesicle acidification. 

Respiration—transport of oxygen from the lungs to the tissues and of COj from the tissues to the lungs Nutrition—transport of absorbed food materials Excretion—transport of metabolic waste to the kidneys, lungs, skin, and intestines for removal Maintenance of the normal acid-base balance in the body... 

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]... 

Structure and physiology of the kidney glomerular filtration tubular activity selective reabsorption and secretion, often using specific carrier mechanisms carbonic anhydrase and acid-base balance. The kidney also produces, and is sensitive to, hormones actions of the hormones ADH, aldosterone and PTH the kidney as a secretory organ erythropoietin, the renin-angiotensin system vitamin D3. 

The balance of filtration at the glomerulus and reabsorption and secretion in the tubules allows the kidneys to maintain homeostasis of extracellular fluid, nutrients and acid-base balance and to excrete drugs and metabolic waste products. 

Carbonate anhydrase (carbonic anhydrase, EC 4.2.1.1) catalyzes the reversible interconversion of C02 and HCO3 (see Sect. 3.7.3). The enzyme is found in erythrocytes, and in kidney and gastric juices where it contributes to the control of the acid-base balance. The esterase activity of carbonic anhydrase is probably due to the similarity between its active site and that of the zinc proteases. A possible physiological role of the esterase activity of this enzyme remains to be established. 

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 pH value is kept constant by buffer systems that cushion minor disturbances in the acid-base balance (C). In the longer term, the decisive aspect is maintaining a balanced equilibrium between H" production and uptake and H" release. If the blood s buffering capacity is not suf cient, or if the acid-base balance is not in equilibrium—e.g., in kidney disease or during hypoventilation or hyperventilation-shifts in the plasma pH value can occur. A reduction by more than 0.03 units is known as acidosis, and an increase is called alkalosis. 

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 change in the acid-base balance in the body also alters the urine pH, making it more acidic (Fig. 7.59). This alters the excretion dynamics of salicylate, because more salicylate becomes nonionized and so is reabsorbed from the kidney tubules into the blood stream rather than being excreted into the urine. As can be seen from the Figure 7.59, lowering the pH of the urine to 6 results in a dramatic decrease in the ionization of the salicylate. Hence, elimination from the body is reduced. 

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 kidneys not only secrete hydrogen ions but they also regenerate bicarbonate ions. The renal handling of electrolytes also influences acid-base balance. 

Because carbohydrate utilization is impaired, a lack of insulin leads to the uncontrolled breakdown of lipids and proteins. Large amounts of acetyl CoA are then produced by P-oxidation. However, much of the acetyl CoA cannot enter the citric acid cycle, because there is insufficient oxaloacetate for the condensation step. Recall that mammals can synthesize oxaloacetate from pyruvate, a product of glycolysis, but not from acetyl CoA instead, they generate ketone bodies. A striking feature of diabetes is the shift in fuel usage from carbohydrates to fats glucose, more abundant than ever, is spurned. In high concentrations, ketone bodies overwhelm the kidney s capacity to maintain acid-base balance. The untreated diabetic can go into a coma because of a lowered blood pH level and dehydration. 

In the intensive care unit muscle relaxants are used to facilitate airway management and mechanical ventilation. The duration of administration can range from a single dose to continuous infusions for up to several weeks. Patients in ICU are more hkely to have abnormalities of acid-base balance, electroljrte balance, body temperature, and liver and kidney function, predisposing them to the adverse effects of neuromuscular blocking drugs. 

If ingested, the formic acid should be diluted with milk or water in alert patients. Careful gastric aspiration with a nasogastric tube may be attempted to limit systemic absorption. The goal of the clinical management is to correct the acidosis. Acidosis may be treated with sodium bicarbonate or by hemodialysis. Immediate hemodialysis may remove formic acid from systemic circulation. Acid-base balance, electrolytes, and kidney function should be monitored closely. 

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. 

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