This encompasses all functions of the kidney, including maintenance of acid-base balance ; regulation abnormal kidney hormones fluid balance ; regulation of sodiumpotassiumand other electrolytes ; clearance of toxins ; absorption of glucoseabnormal kidney hormones, amino acidsand other small molecules; regulation of blood pressure ; production of various hormonessuch as erythropoietin ; and activation of vitamin D.
Much of renal physiology is studied at the level of the nephronthe smallest functional unit of the kidney. Each nephron begins with a filtration component that filters the blood entering the kidney. This filtrate then flows along the length of the nephron, which is a tubular structure abnormal kidney hormones by a single layer of specialized cells and surrounded by capillaries.
The major functions of these lining cells are the reabsorption of water and small molecules from the filtrate into the blood, and the secretion of wastes from the blood into the urine, abnormal kidney hormones. Proper function of the kidney requires that it receives and adequately filters blood, abnormal kidney hormones. A global assessment of renal function is often ascertained by estimating the rate of filtration, called the glomerular filtration rate GFR.
The functions of the kidney can be divided into three groups: The nephron is the functional unit of the kidney. The kidney in humans is capable of producing glucose from lactateglycerol and glutamine. The kidney is responsible for about half of the total gluconeogenesis in fasting humans, abnormal kidney hormones. The regulation of glucose production in the kidney is achieved by action of insulinabnormal kidney hormones, catecholamines and other hormones.
The renal medulla is incapable of producing glucose due to absence of necessary enzymes. The body is very sensitive to its pH. Outside the range of pH that is compatible with life, proteins are denatured and digested, enzymes lose their ability to function, abnormal kidney hormones, and the body is unable to sustain itself.
The kidneys abnormal kidney hormones acid-base homeostasis by regulating the pH of the blood plasma. Gains and losses of acid and base must be balanced. Acids are divided into "volatile acids"  and "nonvolatile acids". The major homeostatic control point for maintaining this stable balance is renal excretion. The kidney is directed to excrete or retain sodium via the action of aldosteroneantidiuretic hormone ADH, or vasopressinatrial natriuretic peptide ANPand other hormones.
Abnormal ranges of the fractional excretion of sodium can imply acute tubular necrosis or glomerular dysfunction. Although the strictest sense of the word excretion with respect to the urinary system is urination itself, renal clearance is also conventionally called excretion for example, in the set term fractional excretion of sodium.
The blood is filtered by nephronsthe functional units of the kidney. Filtration is driven by Starling forces. The ultrafiltrate is passed through, in turn, the proximal convoluted tubulethe loop of Henlethe distal convoluted tubuleand a series of collecting ducts to form urine.
Tubular reabsorption is the process by which solutes and water are removed from the tubular fluid and transported into the blood. It is called reabsorption and not absorption both because these substances have already been absorbed once particularly in the intestines and because the body is reclaiming them from a postglomerular fluid stream that is well on its way to abnormal kidney hormones urine that is, they will soon be lost to the urine unless they are reclaimed.
Reabsorption is a two-step process beginning with the active or passive extraction of substances from the tubule fluid into the renal interstitium the connective tissue that surrounds the nephronsabnormal kidney hormones, and then the transport of these substances from the interstitium into the bloodstream. These transport processes are driven by Starling forcesdiffusionand active transport. In some cases, abnormal kidney hormones, reabsorption is indirect.
Both hormones exert their effects principally on the collecting ducts, abnormal kidney hormones. Tubular secretion occurs simultaneously abnormal kidney hormones reabsorption of Filtrate, abnormal kidney hormones. Substances, generally produced by body or the by-products of cell metabolism that can become toxic in high concentration, and some drugs if taken.
These all are secreted into the lumen of renal tubule. Tubular secretion can be either active or passive or co-transport. Tubular secretion occurs at PCT and DCT; for example, at proximal convoluted tubule, potassium is secreted by means of sodium-potassium pump, hydrogen ion is secreted by means of active transport and co-transport, i.
A simple means of estimating renal function is to measure pHblood urea nitrogenabnormal kidney hormonesand basic electrolytes including sodiumpotassiumchlorideand bicarbonate. As the kidney is the most important organ in controlling these values, any derangement in these values could suggest renal impairment.
From Wikipedia, the free encyclopedia. Redirected from Renal secretion. Its importance in human glucose homeostasis". Characteristics of Proximal Glucose Reabsorption. Proximal Reabsorption of Amino Acids: Proximal Reabsorption of Urea. Excretion of Organic Molecules. Proximal Reabsorption of Bicarbonate.
Proximal Tubular Reabsorption of Bicarbonate. A Cellular And Molecular Approaoch. Physiological Definition of Acids: Measurement of Renal Function. Free water clearance CH2O. Physiology of the kidneys and acid-base physiology, abnormal kidney hormones. Solvent drag abnormal kidney hormones chloride urea glucose oligopeptides protein. Renal blood flow Ultrafiltration Countercurrent exchange Filtration fraction.
Oligopeptidesproteinsand amino acids. All are reabsorbed nearly completely, abnormal kidney hormones. Varies with ADH  . Uses Na-H antiportNa-glucose symport, sodium ion channels minor .
Active transcellular and passive paracellular . Uses aquaporin water channels. Helps maintain acid-base balance. Uses calcium Abnormal kidney hormonessodium-calcium exchanger. Volume of blood plasma delivered to the kidney per unit time. PAH clearance is a renal analysis method used to provide an estimate. Volume of blood delivered to the kidney per unit time.
Usually a creatinine clearance test is performed but other markers, such as the plant polysaccharide inulin or radiolabelled EDTA, may be used as well. Aids in the differential diagnosis of metabolic acidosis. Clearance other than abnormal kidney hormones. The volume of blood plasma that is cleared of solute -free water per unit time. Secretion clearance Pharmacokinetics Clearance of medications Urine flow rate.