Glomerular Filtration Rate
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Glomerular Filtration Rate
Renal functions include maintaining an acid–base balance; regulating fluid balance; regulating sodium, potassium, and other electrolytes; clearance (medicine), clearing toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. The kidney has many functions, which a well-functioning kidney realizes by filtering blood in a process known as glomerular filtration. A major measure of kidney function is the glomerular filtration rate (GFR). The glomerular filtration rate is the flow rate of filtered fluid through the kidney. The creatinine clearance rate (CCr or CrCl) is the volume of blood plasma that is cleared of creatinine per unit time and is a useful measure for approximating the GFR. Creatinine clearance exceeds GFR due to creatinine secretion, which can be blocked by cimetidine. Both GFR and CCr may be accurately calculated by comparative measurement ...
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Physiology Of Nephron
Renal physiology (Latin language, Latin ''renes'', "kidneys") is the study of the physiology of the kidney. This encompasses all functions of the kidney, including maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, and other electrolytes; clearance (medicine), clearance of toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. Much of renal physiology is studied at the level of the nephron, the smallest functional unit of the kidney. Each nephron begins with a #Filtration, filtration component that filters the blood entering the kidney. This filtrate then flows along the length of the nephron, which is a tubular structure lined by a single layer of specialized cell (biology), cells and surrounded by capillary, capillaries. The major functions of these lining cells are the reabsorption of water and small mol ...
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Blood Plasma
Blood plasma is a light Amber (color), amber-colored liquid component of blood in which blood cells are absent, but which contains Blood protein, proteins and other constituents of whole blood in Suspension (chemistry), suspension. It makes up about 55% of the body's total blood volume. It is the Intravascular compartment, intravascular part of extracellular fluid (all body fluid outside cells). It is mostly water (up to 95% by volume), and contains important dissolved proteins (6–8%; e.g., serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (, , , , , etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and oxygen. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood-related disorders. Blood plasma can be separated from whole blood through blood fractionation, by adding an anticoagulant to a tube ...
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Inulin
Inulins are a group of naturally occurring polysaccharides produced by many types of plants, industrially most often extracted from chicory. The inulins belong to a class of dietary fibers known as fructans. Inulin is used by some plants as a means of storing energy and is typically found in roots or rhizomes. Most plants that synthesize and store inulin do not store other forms of carbohydrate such as starch. In 2018, the United States Food and Drug Administration approved inulin as a dietary fiber ingredient used to improve the nutritional value of manufactured food products. Using inulin to measure kidney function is the "gold standard" for comparison with other means of estimating glomerular filtration rate. Origin and history Inulin is a natural storage carbohydrate present in more than 36,000 species of plants, including agave, wheat, onion, bananas, garlic, asparagus, Jerusalem artichoke, and chicory. For these plants, inulin is used as an energy reserve a ...
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Renal Physiology
Renal physiology (Latin language, Latin ''renes'', "kidneys") is the study of the physiology of the kidney. This encompasses all functions of the kidney, including maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, and other electrolytes; clearance (medicine), clearance of toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. Much of renal physiology is studied at the level of the nephron, the smallest functional unit of the kidney. Each nephron begins with a #Filtration, filtration component that filters the blood entering the kidney. This filtrate then flows along the length of the nephron, which is a tubular structure lined by a single layer of specialized cell (biology), cells and surrounded by capillary, capillaries. The major functions of these lining cells are the reabsorption of water and small mol ...
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Creatine Phosphate
Phosphocreatine, also known as creatine phosphate (CP) or PCr (Pcr), is a phosphorylated form of creatine that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle, myocardium and the brain to recycle adenosine triphosphate (ATP), the energy currency of the cell. Chemistry In the kidneys, the enzyme AGAT catalyzes the conversion of two amino acids — arginine and glycine — into guanidinoacetate (also called glycocyamine or GAA), which is then transported in the blood to the liver. A methyl group is added to GAA from the amino acid methionine by the enzyme GAMT, forming non-phosphorylated creatine. This is then released into the blood by the liver where it travels mainly to the muscle cells (95% of the body's creatine is in muscles), and to a lesser extent the brain, heart, and pancreas. Once inside the cells it is transformed into phosphocreatine by the enzyme complex creatine kinase. Phosphocreatine is able to donate its phosphate group to co ...
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Filtration Fraction
In renal physiology, the filtration fraction is the ratio of the glomerular filtration rate (GFR) over the renal plasma flow (RPF). Filtration Fraction, FF = GFR/RPF, or FF = \frac. The filtration fraction, therefore, represents the proportion of the fluid reaching the kidneys that passes into the renal tubules. It is normally about 20%. GFR on its own is the most common and important measure of renal function. However, in conditions such as renal artery stenosis, blood flow to the kidneys is reduced. Filtration fraction must therefore be increased in order to perform the normal functions of the kidney. Loop diuretics and thiazide diuretics decrease filtration fraction. Catecholamines (norepinephrine and epinephrine) increase filtration fraction by vasoconstriction of afferent arteriole, afferent and efferent arterioles, possibly through activation of alpha-1 adrenergic receptors. Severe hemorrhage will also result in an increased filtration fraction. References

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Clearance Rate (biochemistry)
In pharmacology, clearance (Cl_\text) is a pharmacokinetic parameter representing the efficiency of drug elimination. This is the rate of elimination of a substance divided by its concentration. The parameter also indicates the theoretical volume of plasma from which a substance would be completely removed per unit time. Usually, clearance is measured in L/h or mL/min. Excretion, on the other hand, is a measurement of the amount of a substance removed from the body per unit time (e.g., mg/min, μg/min, etc.). While clearance and excretion of a substance are related, they are not the same thing. The concept of clearance was described by Thomas Addis, a graduate of the University of Edinburgh Medical School. Substances in the body can be cleared by various organs, including the kidneys, liver, lungs, etc. Thus, total body clearance is equal to the sum clearance of the substance by each organ (e.g., renal clearance + hepatic clearance + pulmonary clearance = total body clearance). F ...
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Bowman's Capsule
Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sac at the beginning of the Renal tubule, tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus (kidney), glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule. Structure Outside the capsule, there are two poles: * The vascular pole is the side with the afferent arteriole and efferent arteriole. * The tubular pole, is the side with the proximal convoluted tubule. Inside the capsule, the layers are as follows, from outside to inside: *''Parietal layer''—A single layer of simple squamous epithelium. Does not function in filtration. *''Bowman's space (or "urinary space", or "capsular space")''—Between the visceral and parietal layers, into which the filtrate enters after passing through the filtration slits. *''Visceral layer''—Lies just above ...
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Glomerulus (kidney)
The glomerulus (: glomeruli) is a network of small blood vessels (capillaries) known as a ''tuft'', located at the beginning of a nephron in the kidney. Each of the two kidneys contains about one million nephrons. The tuft is structurally supported by the mesangium (the space between the blood vessels), composed of Intraglomerular mesangial cell, intraglomerular mesangial cells. The blood is filtered across the capillary walls of this tuft through the glomerular filtration barrier, which yields its Ultrafiltration (renal), filtrate of water and soluble substances to a cup-like sac known as Bowman's capsule. The filtrate then enters the Nephron#Renal tubule, renal tubule of the nephron. The glomerulus receives its blood supply from an afferent arteriole of the renal arterial circulation. Unlike most capillary beds, the glomerular capillaries exit into efferent arterioles rather than venules. The resistance of the efferent arterioles causes sufficient hydrostatic pressure within th ...
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Kidney Disease
Kidney disease, or renal disease, technically referred to as nephropathy, is damage to or disease of a kidney. Nephritis is an Inflammation, inflammatory kidney disease and has several types according to the location of the inflammation. Inflammation can be diagnosed by blood tests. Nephrosis is non-inflammatory kidney disease. Nephritis and nephrosis can give rise to nephritic syndrome and nephrotic syndrome respectively. Kidney disease usually causes a loss of Assessment of kidney function, kidney function to some degree and can result in kidney failure, the complete loss of kidney function. Kidney failure is known as the end-stage of kidney disease, where Kidney dialysis, dialysis or a Kidney transplantation, kidney transplant is the only treatment option. Chronic kidney disease is defined as prolonged kidney abnormalities (functional and/or structural in nature) that last for more than three months. Acute kidney disease is now termed acute kidney injury and is marked by the ...
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Albuminuria
Albuminuria is a pathological condition of elevated albumin protein in the urine (often measured as urine albumin-to-creatinine ratio of >30 milligrams of albumin per 1 gram of creatinine per day). It is a type of proteinuria, and is the most common protein detected on urinalysis that, when elevated, is associated with kidney and cardiovascular disease (CVD). Albumin is an abundant plasma protein (present in blood) which is normally prevented from being lost into the urine by the sieve-like glomeruli of the nephrons. In healthy people, only trace amounts of it are present in urine, but when the filtration system of the kidney is damaged, larger amounts of albumin escape into the urine, which can be quantified and used to determine the extent of kidney injury/kidney disease. Signs and symptoms Albuminuria is often asymptomatic in low quantities but foamy urine may be present. As significant albumin is lost to the urine, swelling of the ankles, hands, belly or face may occur (see e ...
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Chronic Kidney Disease
Chronic kidney disease (CKD) is a type of long-term kidney disease, defined by the sustained presence of abnormal kidney function and/or abnormal kidney structure. To meet criteria for CKD, the abnormalities must be present for at least three months. Early in the course of CKD, patients are usually asymptomatic, but later symptoms may include pedal edema, leg swelling, feeling tired, vomiting, loss of appetite, and confusion. Complications can relate to hormonal dysfunction of the kidneys and include (in chronological order) Hypertension, high blood pressure (often related to activation of the renin–angiotensin system), renal osteodystrophy, bone disease, and anemia. Additionally CKD patients have markedly increased Cardiovascular disease, cardiovascular complications with increased risks of death and hospitalization. CKD can lead to kidney failure, end-stage kidney failure requiring kidney dialysis or kidney transplantation. Causes of chronic kidney disease include diabetic ne ...
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