the initial stage of blood filtration in the kidneys occurs in which portion of the nephron
renal corpuscle
226692
the kidney is the nephron. It processes the blood supplied to it via filtration, reabsorption, secretion and excretion; the consequence of those processes is the production of urine. Filtration, which takes place at the renal corpuscle, is the process by which cells and large proteins are retained while materials of smaller molecular weights are filtered from the blood to make an ultrafiltrate that eventually becomes urine. The kidney generates 180 liters of filtrate a day. The process is also known as hydrostatic filtration due to the hydrostatic pressure exerted on the capillary walls. Reabsorption is the transport of molecules from
Kidney
1698272
water from within the nephron and returning it to the venous vasculature when appropriate. Some diseases of the nephron predominantly affect either the glomeruli or the tubules. Glomerular diseases include diabetic nephropathy, glomerulonephritis and IgA nephropathy; renal tubular diseases include acute tubular necrosis and polycystic kidney disease. The nephron is the functional unit of the kidney. Each nephron is composed of a renal corpuscle, the initial filtering component; and a renal tubule that processes and carries away the filtered fluid. The renal corpuscle is the site of the filtration of blood plasma. The renal corpuscle consists of the glomerulus, and
Nephron
226692
the kidney is the nephron. It processes the blood supplied to it via filtration, reabsorption, secretion and excretion; the consequence of those processes is the production of urine. Filtration, which takes place at the renal corpuscle, is the process by which cells and large proteins are retained while materials of smaller molecular weights are filtered from the blood to make an ultrafiltrate that eventually becomes urine. The kidney generates 180 liters of filtrate a day. The process is also known as hydrostatic filtration due to the hydrostatic pressure exerted on the capillary walls. Reabsorption is the transport of molecules from
Kidney
2813089
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 nephrons, the functional units of the kidney. Each nephron begins in a renal corpuscle, which is composed of a glomerulus enclosed in a Bowman's capsule. Cells, proteins, and other large molecules are filtered out of the glomerulus by a process of ultrafiltration, leaving an ultrafiltrate that resembles plasma (except that the ultrafiltrate has negligible plasma proteins) to enter Bowman's space. Filtration is driven by Starling forces. The
Renal physiology
226685
renal cortex surrounding a portion of medulla called a renal pyramid. Between the renal pyramids are projections of cortex called renal columns. Nephrons, the urine-producing functional structures of the kidney, span the cortex and medulla. The initial filtering portion of a nephron is the renal corpuscle, which is located in the cortex. This is followed by a renal tubule that passes from the cortex deep into the medullary pyramids. Part of the renal cortex, a medullary ray is a collection of renal tubules that drain into a single collecting duct. The tip, or papilla, of each pyramid empties urine into
Kidney
1698268
well as levels of many body substances. At the end of the tubule, the remaining fluid—urine—exits: it is composed of water, metabolic waste, and toxins. The interior of Bowman's capsule, called Bowman's space, collects the filtrate from the filtering capillaries of the glomerular tuft, which also contains mesangial cells supporting these capillaries. These components function as the filtration unit and make up the renal corpuscle. The filtering structure (glomerular filtration barrier) has three layers composed of endothelial cells, a basement membrane, and podocytes (foot processes). The tubule has five anatomically and functionally different parts: the proximal tubule, which has a
Nephron
226679
kidney participates in the control of the volume of various body fluid compartments, fluid osmolality, acid-base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hydrogen, ammonium, potassium and uric acid. The kidneys also carry out functions independent of the nephron. For example, they convert a precursor of vitamin D to its active form, calcitriol; and synthesize the hormones erythropoietin and renin. Renal physiology is the study
Kidney
226678
Kidney The kidneys are two bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder. The nephron is the structural and functional unit of the kidney. Each adult kidney contains around 1 million nephrons. The nephron utilizes four processes to alter the blood plasma which flows to it: filtration, reabsorption, secretion, and excretion. The
Kidney
2813084
Renal physiology Renal physiology (Latin "rēnēs", "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 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 component that filters the blood entering the kidney.
Renal physiology
17686418
the collecting ducts descend through the medulla, they combine and empty their contents into the ureter. There are two types of avian nephrons, and nephrons become larger as depth from the kidney surface increases. Reptilian-type nephrons are the smallest nephrons, are found near a kidney’s surface, possess simple glomeruli, and do not have loops of Henle. Conversely, between 10% and 30% of the total nephron population is composed of mammalian-type nephrons, which are located in the innermost area of the kidney, have complex glomeruli, and contain loops of Henle. Once the kidneys receive blood, filtration of substances from the blood
Common raven physiology
13189769
Kappa free-light chains are normally monomeric, while lambda free-light chains tend to be dimeric, joined by disulphide bonds. Polymeric forms of both types of free light chain can also occur. In normal individuals, free light chains are rapidly cleared from the blood and catabolised by the kidneys. Monomeric free light chains are cleared in 2–4 hours, and dimeric light chains in 3–6 hours. Removal may be prolonged to 2–3 days in people with complete renal failure. Human kidneys are composed of approximately half a million nephrons. Each nephron contains a glomerulus with basement membrane pores that allow filtration of immunoglobulin
Serum free light-chain measurement
588559
cells of the nephron in the kidney, where all subtypes of dopamine receptors are present. Dopamine is also synthesized there, by tubule cells, and discharged into the tubular fluid. Its actions include increasing the blood supply to the kidneys, increasing the glomerular filtration rate, and increasing the excretion of sodium in the urine. Hence, defects in renal dopamine function can lead to reduced sodium excretion and consequently result in the development of high blood pressure. There is strong evidence that faults in the production of dopamine or in the receptors can result in a number of pathologies including oxidative stress,
Dopamine
6528433
Renal tubular acidosis Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine. In renal physiology, when blood is filtered by the kidney, the filtrate passes through the tubules of the nephron, allowing for exchange of salts, acid equivalents, and other solutes before it drains into the bladder as urine. The metabolic acidosis that results from RTA may be caused either by failure to reabsorb sufficient bicarbonate ions (which are alkaline) from the filtrate in the early portion of the nephron
Renal tubular acidosis
1698269
convoluted section the proximal convoluted tubule followed by a straight section (proximal straight tubule); the loop of Henle, which has two parts, the descending loop of Henle ("descending loop") and the ascending loop of Henle ("ascending loop"); the distal convoluted tubule ("distal loop"); the connecting tubule, and the collecting ducts. Nephrons have two lengths with different urine concentrating capacities: long juxtamedullary nephrons and short cortical nephrons. The four mechanisms used to create and process the filtrate (the result of which is to convert blood to urine) are filtration, reabsorption, secretion and excretion. Filtration occurs in the glomerulus and is largely
Nephron
750321
synthesized in the kidney from the amino acids arginine and glycine) by S-adenosyl methionine. It is then transported through blood to the other organs, muscle, and brain, where, through phosphorylation, it becomes the high-energy compound phosphocreatine. Creatine conversion to phosphocreatine is catalyzed by creatine kinase; spontaneous formation of creatinine occurs during the reaction. Creatinine is removed from the blood chiefly by the kidneys, primarily by glomerular filtration, but also by proximal tubular secretion. Little or no tubular reabsorption of creatinine occurs. If the filtration in the kidney is deficient, creatinine blood levels rise. Therefore, creatinine levels in blood and urine
Creatinine
662893
too little urine requires medical attention. Polyuria is a condition of excessive urine production (> 2.5 L/day). Oliguria when < 400 mL (millilitres) are produced, and anuria one of < 100 mL per day. The first step in urine formation is the filtration of blood in the kidneys. In a healthy human the kidney receives between 12 and 30% of cardiac output, but it averages about 20% or about 1.25 L/min. The basic structural and functional unit of the kidney is the nephron. Its chief function is to regulate the concentration of water and soluble substances like sodium by filtering
Urinary system
2047338
with cellular matter, particularly necrotic sloughing of dead cells. This debris obstructs the flow of filtrate, which results in reduced output of urine. The arterial supply of the nephron is linked to the filtration apparatus (glomerulus), and reduced perfusion leads to reduced blood flow; usually this is the result of pre-renal pathology. The kidney's resorptive mechanisms are particularly energetic, using nearly 100% of the O supplied. Thus, the kidney is particularly sensitive to reduction in blood supply. This phenomenon occurs because renal flow is restored prior to the normal resorption function of the renal tubule. As you can see in
Diuresis
8992024
blood filtration by the nephron) is particularly sensitive to changes in blood pressure. However, with the aid of the myogenic mechanism, the glomerular filtration rate remains very insensitive to changes in human blood pressure. Myogenic mechanisms in the kidney are part of the autoregulation mechanism which maintains a constant renal blood flow at varying arterial pressure. Concomitant autoregulation of glomerular pressure and filtration indicates regulation of preglomerular resistance. Model and experimental studies were performed to evaluate two mechanisms in the kidney, myogenic response and tubuloglomerular feedback. A mathematical model showed good autoregulation through a myogenic response, aimed at maintaining a
Myogenic mechanism
18171775
Vitamin and mineral supplementation for dialysis patients When healthy, the kidneys are responsible for the continuous filtration of blood in order to maintain fluid, electrolyte, and organic solute balance in the body. However, when the kidneys are damaged, they are no longer able to do this. Dialysis, used in end stage renal disease (also referred to as renal failure, chronic kidney disease, and kidney failure), it is a process where a machine filters the blood since the kidneys are no longer able to. In addition to the inability to filter blood, renal failure results in the body’s inability to make
Vitamin and mineral supplementation for dialysis patients
7972382
affected. A high protein diet affects the feedback activity by making the single nephron glomerular filtration rate higher, and the Na and Cl concentrations in early distal tubule fluid lower. The signal eliciting the TG feedback response is affected. The increased load on the kidney of high-protein diet is a result of an increase in reabsorption of NaC. Factors that "increase" TGF sensitivity include: Tubuloglomerular feedback In the physiology of the kidney, tubuloglomerular feedback (TGF) is a feedback system inside the kidneys. Within each nephron, information from the renal tubules (a downstream area of the tubular fluid) is signaled to
Tubuloglomerular feedback
662894
the blood, reabsorbing what is needed and excreting the rest as urine. In the first part of the nephron, Bowman's capsule filters blood from the circulatory system into the tubules. Hydrostatic and osmotic pressure gradients facilitate filtration across a semipermeable membrane. The filtrate includes water, small molecules, and ions that easily pass through the filtration membrane. However larger molecules such as proteins and blood cells are prevented from passing through the filtration membrane. The amount of filtrate produced every minute is called the glomerular filtration rate or GFR and amounts to 180 litres per day. About 99% of this filtrate
Urinary system
6528434
(the proximal tubule) or by insufficient secretion of hydrogen ions (which are acidic) into the latter portions of the nephron (the distal tubule). Although a metabolic acidosis also occurs in those with renal insufficiency, the term RTA is reserved for individuals with poor urinary acidification in otherwise well-functioning kidneys. Several different types of RTA exist, which all have different syndromes and different causes. The word "acidosis" refers to the tendency for RTA to cause an excess of acid, which lowers the blood's pH. When the blood pH is below normal (7.35), this is called "acidemia". The metabolic acidosis caused by
Renal tubular acidosis
226696
of urine much smaller than the volume of blood from which the wastes were extracted is dependent on an elaborate countercurrent multiplication mechanism. This requires several independent nephron characteristics to operate: a tight hairpin configuration of the tubules, water and ion permeability in the descending limb of the loop, water impermeability in the ascending loop, and active ion transport out of most of the ascending limb. In addition, passive countercurrent exchange by the vessels carrying the blood supply to the nephron is essential for enabling this function. Two organ systems, the kidneys and lungs, maintain acid-base homeostasis, which is the
Kidney
1698277
start low in the cortex near the medulla and have a long loop of Henle which penetrates deeply into the renal medulla: only they have their loop of Henle surrounded by the vasa recta. These long loops of Henle and their associated vasa recta create a hyperosmolar gradient that allows for the generation of a concentrated urine. The nephron uses four mechanisms to convert blood into urine: filtration, reabsorption, secretion, and excretion of numerous substances. The structure and function of the epithelial cells lining the lumen change during the course of the nephron, and have segments named by their location
Nephron
3113569
Glomerulus (kidney) The glomerulus (), plural glomeruli, is a network of capillaries known as a "tuft", located at the beginning of a nephron in the kidney. The tuft is structurally supported by intraglomerular mesangial cells. The blood is filtered across the capillary walls of this tuft through the glomerular filtration barrier, which yields its filtrate of water and soluble substances to a cup-like sac known as Bowman's capsule. The filtrate then enters the 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
Glomerulus (kidney)
5743225
renal plasma clearance. Each substance has a specific clearance that depends on its filtration characteristics. Clearance is a function of glomerular filtration, secretion from the peritubular capillaries to the nephron, and re-absorption from the nephron back to the peritubular capillaries. Clearance is variable in zero-order kinetics because a constant amount of the drug is eliminated per unit time, but it is constant in first-order kinetics, because the amount of drug eliminated per unit time changes with the concentration of drug in the blood. The concept of clearance was described by Thomas Addis, a graduate of the University of Edinburgh Medical
Clearance (pharmacology)
226687
left and right, which branch directly from the abdominal aorta. Despite their relatively small size, the kidneys receive approximately 20% of the cardiac output. Each renal artery branches into segmental arteries, dividing further into interlobar arteries, which penetrate the renal capsule and extend through the renal columns between the renal pyramids. The interlobar arteries then supply blood to the arcuate arteries that run through the boundary of the cortex and the medulla. Each arcuate artery supplies several interlobular arteries that feed into the afferent arterioles that supply the glomeruli. After filtration occurs, the blood moves through a small network of
Kidney
10047763
Filtration fraction In renal physiology, the filtration fraction is the ratio of the glomerular filtration rate (GFR) to the renal plasma flow (RPF). Filtration Fraction, FF = GFR/RPF, or formula_1. 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
Filtration fraction
662888
Urinary system The urinary system, also known as the renal system or urinary tract, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH. The urinary tract is the body's drainage system for the eventual removal of urine. The kidneys have an extensive blood supply via the renal arteries which leave the kidneys via the renal vein. Each kidney consists of functional units called nephrons. Following filtration of blood and further processing,
Urinary system
2676291
Juxtaglomerular apparatus The juxtaglomerular apparatus (also known as the juxtaglomerular complex) is a structure in the kidney that regulates the function of each nephron, the functional units of the kidney. The juxtaglomerular apparatus is named because it is next to (juxta-) the glomerulus. The juxtaglomerular apparatus consists of three types of cells: The juxtaglomerular apparatus is part of the kidney nephron, next to the glomerulus. It is found between afferent arteriole and the distal convoluted tubule of the same nephron. This location is critical to its function in regulating renal blood flow and glomerular filtration rate.The swollen smooth muscle cells
Juxtaglomerular apparatus
2708707
is not used widely anymore, probably to avoid confusion with Malpighian bodies of the spleen. Bowman's capsule Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sack at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule (i.e., glomerular filtrate) and further processed along the nephron to form urine. This process is known as ultrafiltration.The Bowman's capsule is named
Bowman's capsule
2708703
Bowman's capsule Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sack at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule (i.e., glomerular filtrate) and further processed along the nephron to form urine. This process is known as ultrafiltration.The Bowman's capsule is named after Sir William Bowman, who identified it in 1842. Outside the capsule, there are two
Bowman's capsule
7972372
Tubuloglomerular feedback In the physiology of the kidney, tubuloglomerular feedback (TGF) is a feedback system inside the kidneys. Within each nephron, information from the renal tubules (a downstream area of the tubular fluid) is signaled to the glomerulus (an upstream area). Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signaling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level. The kidney
Tubuloglomerular feedback
3113581
Bowman elucidated in detail the capillary architecture of the glomerulus and the continuity between its surrounding capsule and the proximal tubule. Glomerulus (kidney) The glomerulus (), plural glomeruli, is a network of capillaries known as a "tuft", located at the beginning of a nephron in the kidney. The tuft is structurally supported by intraglomerular mesangial cells. The blood is filtered across the capillary walls of this tuft through the glomerular filtration barrier, which yields its filtrate of water and soluble substances to a cup-like sac known as Bowman's capsule. The filtrate then enters the renal tubule, of the nephron. The
Glomerulus (kidney)
7519629
cloaca, while in others it forms along the length of the intermediate mesoderm. In both amphibians and zebrafish the pronephros has a single nephron attached to a nephric duct, which in turn is linked to the cloaca. Although these kidneys have a simple anatomical organization with only a single nephron, the nephrons have a segmental and functional complexity that is very similar to that in more complex kidneys such as mesonephroi and metanephroi. One unique feature of pronephroi is the arrangement by which the glomerular filtrate is generated and collected by the nephron. In pronephroi the glomerulus (or glomus if
Pronephros
17686417
wastes and excess water and solutes. Like other birds, the common raven is considered a uricotelic organism with an osmoregulatory system consisting of a pair of kidneys that constitute 0.8% of its body mass. Similar to mammalian species, the functional units of avian kidneys are the nephrons. Externally, the kidneys are elongated and have three lobes, and the inner portion contains a cortex and medulla. Within the cortex, nephrons are organized around central veins of the efferent venous system. In contrast, the medulla is structured into medullary cones that contain nephron elements, specifically collecting ducts and loops of Henle. As
Common raven physiology
2813085
This filtrate then flows along the length of the nephron, which is a tubular structure lined 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. Proper function of the kidney requires that it receives and adequately filters blood. This is performed at the microscopic level by many hundreds of thousands of filtration units called renal corpuscles, each of which is composed of a glomerulus and a
Renal physiology
17686420
an osmolarity that is two to three times the osmolarity of plasma. Glomerular filtration only accounts for 10% to 20% of urinary urate. Greater than 90% of urate excreted by the kidneys is derived from the process of secretion. The osmoregulatory system is interconnected with the circulatory system to permit effective regulation of salt and water balance. Circulatory fluids function in renal clearance, which is the blood volume that substances are removed from within the kidneys during a certain time period. In addition to filtration, the circulatory system also plays a role in reabsorption. Furthermore, the role of the renal
Common raven physiology
1789437
As the kidneys reabsorb more water from the filtrate, myoglobin interacts with Tamm–Horsfall protein in the nephron to form casts (solid aggregates) that obstruct the normal flow of fluid; the condition is worsened further by high levels of uric acid and acidification of the filtrate, which increase cast formation. Iron released from the heme generates reactive oxygen species, damaging the kidney cells. In addition to the myoglobinuria, two other mechanisms contribute to kidney impairment: low blood pressure leads to constriction of the blood vessels and therefore a relative lack of blood flow to the kidney, and finally uric acid may
Rhabdomyolysis
11367073
PAH clearance Para-aminohippurate (PAH) clearance is a method used in renal physiology to measure renal plasma flow, which is a measure of renal function. PAH is completely removed from blood that passes through the kidneys (PAH undergoes both glomerular filtration and tubular secretion), and therefore the rate at which the kidneys can clear PAH from the blood reflects total renal plasma flow. The concentration of PAH is measured in one arterial blood sample (P) and one urine sample(U). The urine flow (V) is also measured. Renal perfusion flow is then calculated by: What is calculated is the effective renal plasma
PAH clearance
5940621
Renal replacement therapy Renal replacement therapy (RRT) is therapy that replaces the normal blood-filtering function of the kidneys. It is used when the kidneys are not working well, which is called renal failure and includes acute kidney injury and chronic kidney disease. Renal replacement therapy includes dialysis (hemodialysis or peritoneal dialysis), hemofiltration, and hemodiafiltration, which are various ways of filtration of blood with or without machines. Renal replacement therapy also includes kidney transplantation, which is the ultimate form of replacement in that the old kidney is replaced by a donor kidney. These treatments are not truly cures for kidney disease.
Renal replacement therapy
3113576
of the medullary countercurrent exchange system. The filtrate that has passed through the three-layered filtration unit enters Bowman's space. From there, it flows into the renal tubule - the nephron - which follows a U-shaped path to the collecting ducts, finally exiting into a renal calyx as urine. The main function of the glomerulus is to filter plasma to produce glomerular filtrate, which passes down the length of the nephron tubule to form urine. The rate at which the glomerulus produces filtrate from plasma (the glomerular filtration rate) is much higher than in systemic capillaries because of the particular anatomical
Glomerulus (kidney)
2813086
Bowman's capsule. 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: secretion of hormones, gluconeogenesis and extracellular homeostasis of pH and blood components. The nephron is the functional unit of the kidney. The kidney in humans is capable of producing glucose from lactate, glycerol and glutamine. The kidney is responsible for about half of the total gluconeogenesis in fasting humans. The regulation of glucose production in the kidney is achieved by action of insulin, catecholamines and other
Renal physiology
274371
Mass transfer Mass transfer is the net movement of mass from one location, usually meaning stream, phase, fraction or component, to another. Mass transfer occurs in many processes, such as absorption, evaporation, drying, precipitation, membrane filtration, and distillation. Mass transfer is used by different scientific disciplines for different processes and mechanisms. The phrase is commonly used in engineering for physical processes that involve diffusive and convective transport of chemical species within physical systems. Some common examples of mass transfer processes are the evaporation of water from a pond to the atmosphere, the purification of blood in the kidneys and liver,
Mass transfer
1698278
and which reflects their different functions. The proximal tubule as a part of the nephron can be divided into an initial convoluted portion and a following straight (descending) portion. Fluid in the filtrate entering the proximal convoluted tubule is reabsorbed into the peritubular capillaries, including approximately two-thirds of the filtered salt and water and all filtered organic solutes (primarily glucose and amino acids). The loop of Henle is a U-shaped tube that extends from the proximal tubule. It consists of a descending limb and an ascending limb. It begins in the cortex, receiving filtrate from the proximal convoluted tubule, extends
Nephron
17686419
into urine takes place. The glomerular filtration rate of single nephrons in birds is low because avian glomeruli have small surface area. Through the process of reabsorption, the majority of the fluid volume and solutes are transported from the urine to the blood. Next, secretion of materials from the renal epithelia into the urine occurs. Finally, urine as the end product travels to the ureters to be excreted. The kidneys of a common raven filter about eleven times its total body water daily, and more than 95% of the filtered water is reabsorbed. Urine of birds is typically concentrated to
Common raven physiology
19034142
of sodium and fluids in the nephron and thereby tend to reduce blood pressure. As indicated above, 20-HETE may raise blood pressure by constricting arterial blood vessels but also may lower blood pressure by promoting the loss of sodium and fluids in the kidneys. The effects of 20-HETE therefore are complex, as indicated in studies of the following animal models. Many of these models appear relevant to hypertension in humans in that they parallel the human disease, i.e. men have higher rates of hypertension than women, and women with increased levels of androgens (e.g. postmenopausal women and women with polycystic
20-Hydroxyeicosatetraenoic acid
301725
a fairly reliable marker of glomerular filtration rate (GFR). It has been seen that during normal hydration within the kidneys, the glomerular filtration rate is approximately 92 ml/min. However, when an ostrich experiences dehydration for at least 48 hours (2 days), this value diminishes to only 25% of the hydrated GFR rate. Thus in response to the dehydration, ostrich kidneys secrete small amounts of very viscous glomerular filtrates that have not been broken down, and return them to the circulatory system through blood vessels. The reduction of GFR during dehydration is extremely high, and so the fractional excretion of water
Common ostrich
8992023
increase or decrease blood flow. The smooth muscle of the blood vessels reacts to the stretching of the muscle by opening ion channels, which cause the muscle to depolarize, leading to muscle contraction. This significantly reduces the volume of blood able to pass through the lumen, which reduces blood flow through the blood vessel. Alternatively when the smooth muscle in the blood vessel relaxes, the ion channels close, resulting in vasodilation of the blood vessel; this increases the rate of flow through the lumen. This system is especially significant in the kidneys, where the glomerular filtration rate (the rate of
Myogenic mechanism
3558415
ionic salts are able to pass through the filtration slits and form an ultrafiltrate in the tubular fluid, which is further processed by the nephron to produce urine. Podocytes are also involved in regulation of glomerular filtration rate (GFR). When podocytes contract, they cause closure of filtration slits. This decreases the GFR by reducing the surface area available for filtration. A Loss of the foot processes of the podocytes (i.e., podocyte effacement) is a hallmark of minimal change disease, which has therefore sometimes been called foot process disease. Disruption of the filtration slits or destruction of the podocytes can lead
Podocyte
7972375
in the nephron by the macula densa (MD), cells in the tubular wall near the end of TAL and the glomerulus. The muscle tension in the afferent arteriole is modified based on the difference between the sensed concentration and a target concentration. Vasodilation of the afferent arteriole, which results in increased glomerular filtration pressure and tubular fluid flow, occurs when MD cells detect a chloride concentration that is below a target value. A higher fluid flow rate in the TAL allows less time for dilution of the tubular fluid so that MD chloride concentration increases. Glomerular flow is decreased if
Tubuloglomerular feedback
5505118
calcium than it loses by hormonal stimulation of osteoclasts. Only when there are conditions, such as dietary calcium deficiency or defects in intestinal transport, which result in a reduction of serum calcium does an overall loss of calcium from bone occur. Calcitriol also inhibits the release of calcitonin, a hormone which reduces blood calcium primarily by inhibiting calcium release from bone. (The effect of calcitonin on renal excretion is disputed.) Calcitriol is produced in the cells of the proximal tubule of the nephron in the kidneys by the action of 25-hydroxyvitamin D 1-alpha-hydroxylase, a mitochondrial oxygenase and an enzyme which
Calcitriol
2637896
exactly the same as the principal cells of the nephron. These responses are important in climate adaptation and as a cause of constipation with elevated aldosterone. The sodium retention leads to plasma volume expansion and elevated blood pressure. The increased blood pressure will lead to increased glomerular filtration rate and cause a decrease in renin release from the granular cells of the juxtaglomerular apparatus in the kidney decreasing sodium reabsorption and returning sodium renal excretion to near normal levels allowing sodium to 'escape' the effect of mineralocorticoids (also known as Aldosterone escape mechanism in primary hyperaldosteronism also contributed to by
Primary aldosteronism
4872188
condition, when a high amount of carbohydrate is taken, it is rapidly absorbed in some cases where a part of the stomach is surgically removed, the excessive glucose appears in urine producing glucosuria. Blood is filtered by millions of nephrons, the functional units that comprise the kidneys. In each nephron, blood flows from the arteriole into the glomerulus, a tuft of leaky capillaries. The Bowman's capsule surrounds each glomerulus, and collects the filtrate that the glomerulus forms. The filtrate contains waste products (e.g. urea), electrolytes (e.g. sodium, potassium, chloride), amino acids, and glucose. The filtrate passes into the renal tubules
Glycosuria
11356409
ions in the blood plasma. About 40% of the urea filtered is normally found in the final urine, since there is more reabsorption than secretion along the nephron. It is regulated by antidiuretic hormone, which controls the amount reabsorbed in the collecting duct system and secreted into the loop of Henle. Renal urea handling Renal urea handling is the part of renal physiology that deals with the reabsorption and secretion of urea. Movement of large amounts of urea across cell membranes is made possible by urea transporter proteins. Urea allows the kidneys to create hyperosmotic urine (urine that has more
Renal urea handling
7305953
cranial-to-caudal direction. As it elongates caudally, the pronephric duct induces nearby intermediate mesoderm in the thoracolumbar area to become epithelial tubules called mesonephric tubules. Each mesonephric tubule receives a blood supply from a branch of the aorta, ending in a capillary tuft analogous to the glomerulus of the definitive nephron. The mesonephric tubule forms a capsule around the capillary tuft, allowing for filtration of blood. This filtrate flows through the mesonephric tubule and is drained into the continuation of the pronephric duct, now called the mesonephric duct or Wolffian duct. The nephrotomes of the pronephros degenerate while the mesonephric duct
Kidney development
3558416
to massive proteinuria, where large amounts of protein are lost from the blood. An example of this occurs in the congenital disorder Finnish-type nephrosis, which is characterised by neonatal proteinuria leading to end-stage renal failure. This disease has been found to be caused by a mutation in the nephrin gene. Presence of podocytes in urine has been proposed as an early diagnostic marker for preeclampsia. Podocyte Podocytes are cells in the Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. The Bowman's capsule filters the blood, retaining large molecules such as proteins while smaller molecules such as
Podocyte
9906412
control over its kidneys. It is able to switch at will between the right or left kidney doing the bulk of the filtration, and can also regulate the filtration rate so that the rate does not increase when the animal's blood pressure goes up due to stress or exercise. Some species of Octopus, including "O. vulgaris", also have a duct that runs from the gonadal space into the branchial pericardium. Wells theorized that this duct, which is highly vascularized and innervated, may enable the reabsorption of important metabolites from the ovisac fluid of pregnant females by directing this fluid into
Common octopus
1212901
algae can result in the eutrophication of a body of water. Oyster filtration can mitigate these pollutants. In addition to their gills, oysters can also exchange gases across their mantles, which are lined with many small, thin-walled blood vessels. A small, three-chambered heart, lying under the adductor muscle, pumps colorless blood to all parts of the body. At the same time, two kidneys, located on the underside of the muscle, remove waste products from the blood. Their nervous system includes two pairs of nerve cords and three pairs of ganglia. While some oysters have two sexes (European oyster and Olympia
Oyster
10422772
name, Senior-Loken syndrome. The diagnosis of nephronophthisis can be obtained via a kidney ultrasound, family history and clinical history of the affected individual according to Stockman, et al. The management of this condition can be done via-improvement of any electrolyte imbalance, as well as, high blood pressure and low red blood cell counts (anemia) treatment as the individual's condition warrants. Nephronophthisis occurs equally in both sexes and has an estimate 9 in about 8 million rate in individuals. Nephronophthisis is the leading monogenic cause of end-stage kidney disease. Nephronophthisis Nephronophthisis is a genetic disorder of the kidneys which affects children.
Nephronophthisis
1936927
feedback, preventing an excessive rise in GFR. Angiotensin II causes the local release of prostaglandins, which, in turn, antagonize renal vasoconstriction. The net effect of these competing mechanisms on glomerular filtration will vary with the physiological and pharmacological environment. Angiotensin Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex to promote sodium retention by the kidneys. An oligopeptide, angiotensin is a hormone and a dipsogen. It is derived from the precursor molecule angiotensinogen,
Angiotensin
11446078
enzyme-linked immunosorbent assay (ELISA) which detect the antibodies specific to thrombosis carried by the biomarkers injected in the patient. According to the International Center for Materials Nanoarchitechtonics (MANA) a new technique, using nanoparticles, could be used for blood filtration in the kidneys eliminating the need for kidney dialysis with this new method. They say that this new nanofiber would be more effective than dialysis because it is not electric dependent and also cheaper which would make it more available than our current dialysis treatments. The nanofiber mesh is made from particles that are blood compatible and also other natural occurring
Nanonephrology
7335374
been reported to FDA and described in the literature since these were issued." When a kidney damaged by phosphate nephropathy is biopsied, the pathological findings are typical of nephrocalcinosis: diffuse tubular injury with calcium phosphate crystal deposition. Phosphate nephropathy Phosphate nephropathy consists of damage to the kidneys caused by the formation of phosphate crystals within the kidney's tubules, damaging the nephron, and can cause acute kidney failure. Phosphate nephropathy frequently occurs following the ingestion of oral sodium phosphate laxatives such as C.B. Fleet's Phospho soda and Salix's Visocol taken for bowel cleansing prior to a colonoscopy. The risk of this
Phosphate nephropathy
7335372
Phosphate nephropathy Phosphate nephropathy consists of damage to the kidneys caused by the formation of phosphate crystals within the kidney's tubules, damaging the nephron, and can cause acute kidney failure. Phosphate nephropathy frequently occurs following the ingestion of oral sodium phosphate laxatives such as C.B. Fleet's Phospho soda and Salix's Visocol taken for bowel cleansing prior to a colonoscopy. The risk of this complication is increased with age, dehydration, or in the presence of hypertension or if the patient is taking an ACE inhibitor or angiotensin receptor blocker. Other agents used for bowel preparation (e.g. magnesium citrate or PEG-3350 &
Phosphate nephropathy
1346149
dysfunction, burning sensations at finger tips, and an increased vulnerability to opportunistic fungal and viral infections. Ciclosporin causes hypertension by inducing vasoconstriction in the kidneys and increasing sodium reabsorption. The increase in blood pressure can cause cardiovascular events; it is thus recommended that the lowest effective dose for people requiring long-term treatment be used. Ciclosporin use after a kidney transplantation is associated with increased levels of uric acid in the blood and, in some cases, gout. This is due to the decrease in glomerular filtration rate, which leads to uric acid retention. Use of azathioprine as an alternative has shown
Ciclosporin
9771594
up of organs with a lower blood flow. Other tissues, such as the brain, can occupy a variable position depending on a drug’s ability to cross the barrier that separates the organ from the blood supply. This "two compartment model" will vary depending on which compartment elimination occurs in. The most common situation is that elimination occurs in the central compartment as the liver and kidneys are organs with a good blood supply. However, in some situations it may be that elimination occurs in the peripheral compartment or even in both. This can mean that there are three possible variations
Pharmacokinetics
1698270
passive: it is dependent on the intracapillary blood pressure. About one-fifth of the plasma is filtered as the blood passes through the glomerular capillaries; four-fifths continues into the peritubular capillaries. Normally the only components of the blood that are not filtered into Bowman's capsule are blood proteins, red blood cells, white blood cells and platelets. Over 150 liters of fluid enter the glomeruli of an adult every day: 99% of the water in that filtrate is reabsorbed. Reabsorption occurs in the renal tubules and is either passive, due to diffusion, or active, due to pumping against a concentration gradient. Secretion
Nephron
1698275
glomerulus are filtered through the visceral layer of podocytes, resulting in the glomerular filtrate. The glomerular filtrate next moves to the renal tubule, where it is further processed to form urine. The different stages of this fluid are collectively known as the tubular fluid. The renal tubule is the portion of the nephron containing the tubular fluid filtered through the glomerulus. After passing through the renal tubule, the filtrate continues to the collecting duct system. The components of the renal tubule are: Blood from the efferent arteriole, containing everything that was not filtered out in the glomerulus, moves into the
Nephron
18793519
of dapagliflozin, therefore it can be administered without regard to meals. These are the known members of the gliflozin class: Sodium Glucose cotransporters (SGLTs) are proteins that occur primarily in the kidneys and play an important role in maintaining glucose balance in the blood. SGLT1 and SGLT2 are the two most know SGLTs of this family. SGLT2 is the major transport protein and promotes reabsorption from the glomerular filtration glucose back into circulation and is responsible for approximately 90% of the kidney's glucose reabsorption. SGLT2 is mainly expressed in the kidneys on the epithelial cells lining the first segment of
Gliflozin
5770019
fluid loss by reducing urine output (the kidneys must produce at least some urine in order to excrete metabolic waste.) Oral rehydration therapy (ORT), is type of fluid replacement used as a treatment for dehydration. In an acute hospital setting, fluid balance is monitored carefully. This provides information on the patient's state of hydration, renal function and cardiovascular function. If blood pressure is low (hypotension), the filtration rate in the kidneys will lessen, causing less fluid reabsorption and thus less urine output. An accurate measure of fluid balance is therefore an important diagnostic tool, and allows for prompt intervention to
Fluid balance
4517691
kidneys leading to reduced kidney function and, possibly, renal failure. Renal artery The renal arteries normally arise off the left interior side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys. It has a radius of approximately 0.25 cm, 0.26 cm at
Renal artery
1974050
person. Someone in early stage kidney disease may not feel sick or notice symptoms as they occur. When kidneys fail to filter properly, waste accumulates in the blood and the body, a condition called azotemia. Very low levels of azotaemia may produce few, if any, symptoms. If the disease progresses, symptoms become noticeable (if the failure is of sufficient degree to cause symptoms). Kidney failure accompanied by noticeable symptoms is termed uraemia. Symptoms of kidney failure include the following: Acute kidney injury (previously known as acute renal failure) – or AKI – usually occurs when the blood supply to the
Kidney failure
549812
the glomerular filtration rate and enhancing the absorption of sodium and water in the proximal nephron. Less fluid reaches the distal nephron, so overall fluid conservation is obtained. Lithium-induced nephrogenic DI may be effectively managed with the administration of amiloride, a potassium-sparing diuretic often used in conjunction with thiazide or loop diuretics. Clinicians have been aware of lithium toxicity for many years, and traditionally have administered thiazide diuretics for lithium-induced polyuria and nephrogenic diabetes insipidus. However, amiloride has recently been shown to be a successful treatment for this condition. The word "diabetes" ( or ) comes from Latin "diabētēs", which
Diabetes insipidus
4762059
to increase blood flow to the kidney perfusion and increase glomerular filtration across undamaged glomeruli. Diagnosis of HN is made from a clinical history and biochemical investigations. Chronic hypertension with progressive kidney disease progresses over a long period of time. Damage to the glomeruli allows proteins that are usually too large to pass into the nephron to be filtered. This leads to an elevated concentration of albumin in the urine (albuminuria). This albuminuria usually does not cause symptoms but can be indicative of many kidney disorders. Protein in the urine (proteinuria) is best identified from a 24-hour urine collection. Bilateral
Hypertensive kidney disease
16624659
of the embryonic kidney, using a pool of six genes of instructive transcription factors (SIX1, SIX2, OSR1, Eyes absent homolog 1(EYA1), Homeobox A11 (HOXA11) and Snail homolog 2 (SNAI2)) that activated genes consistent with a cap mesenchyme/nephron progenitor phenotype in the adult proximal tubule cell line. The generation of such cells may lead to cellular therapies for adult renal disease. Embryonic kidney organoids placed into adult rat kidneys can undergo onward development and vascular development. As blood vessels age, they often become abnormal in structure and function, thereby contributing to numerous age-associated diseases including myocardial infarction, ischemic stroke and atherosclerosis
Induced stem cells
1730018
blood pressure. A third function is possible. Some AVP may be released directly into the brain from the hypothalamus, and may play an important role in social behavior, sexual motivation and pair bonding, and maternal responses to stress. Vasopressin induces differential of stem cells into cardiomyocytes and promotes heart muscle homeostasis. It has a very short half-life, between 16–24 minutes. Vasopressin regulates the tonicity of body fluids. It is released from the posterior pituitary in response to hypertonicity and causes the kidneys to reabsorb solute-free water and return it to the circulation from the tubules of the nephron, thus returning
Vasopressin
10177597
side-effects. Creatinine is the most widely used biomarker of kidney function. It is inaccurate at detecting mild renal impairment, and levels can vary with muscle mass but not with protein intake. Urea levels might change with protein intake. Formulas such as the Cockcroft and Gault formula and the MDRD formula (see Renal function) try to adjust for these variables. Cystatin C has a low molecular weight (approximately 13.3 kilodaltons), and it is removed from the bloodstream by glomerular filtration in the kidneys. If kidney function and glomerular filtration rate decline, the blood levels of cystatin C rise. Cross-sectional studies (based
Cystatin C
16126726
device’s looping channels strives to simulate the countercurrent mechanism of the loop of Henle. Likewise, the loop of Henle requires a number of different cell types because each cell type has distinct transport properties and characteristics. These include the descending limb cells, thin ascending limb cells, thick ascending limb cells, cortical collecting duct cells and medullary collecting duct cells. One step towards validating the microfluidic device’s simulation of the full filtration and reabsorption behavior of a physiological nephron would include demonstrating that the transport properties between blood and filtrate are identical with regards to where they occur and what is
Organ-on-a-chip
19207499
normal renal functioning. However, in the harvest season, when the workers were constantly exposed to smoke and ash from burnt sugarcane, blood and urine samples from the subjects showed a 20% decrease in the rate of renal filtration that caused an increased in blood-level creatinine, a marker of acute renal strain or failure. The exposure to burnt sugarcane corresponded with kidneys not properly functioning, and higher levels of toxins in the blood as a consequence. While no such study has been done on Maui, the harvesting process in the Brazilian study is essentially identical to HC&S's burnt-harvesting process. Another Brazilian
Health effects of the sugarcane industry on Maui
12472192
and movement. This is caused by increased metabolism in areas of the brain associated with movement, such as the nigrostriatal pathway. This causes reward systems in the brain to become more active, which may induce certain individuals to behave in an uncharacteristically loud and cheerful manner. Alcohol has been known to mitigate the production of antidiuretic hormone, which is a hormone that acts on the kidney to favor water reabsorption in the kidneys during filtration. This occurs because alcohol confuses osmoreceptors in the hypothalamus, which relay osmotic pressure information to the posterior pituitary, the site of antidiuretic hormone release. Alcohol
Short-term effects of alcohol consumption
7519627
nephron that processes blood filtrate produced from glomeruli or glomera- large embryonic glomeruli. The filtrate is deposited into the coelom. It then passes through thin ciliated tubules into the pronephric nephron where it is processed for solute recovery. The organ is active in adult forms of some primitive fish, like lampreys or hagfish. It is present at the embryo of more advanced fish and at the larval stage of amphibians where it plays an essential role in osmoregulation. In human beings, it is rudimentary, appears at the end of the third week (day 20) and replaced by mesonephros after 3.5
Pronephros
28384
hormones produced from the cortex of the adrenal gland, from which they are named. Corticosteroids are named according to their actions: The adrenal gland produces aldosterone, a mineralocorticoid, which is important in the regulation of salt ("mineral") balance and blood volume. In the kidneys, aldosterone acts on the distal convoluted tubules and the collecting ducts by increasing the reabsorption of sodium and the excretion of both potassium and hydrogen ions. Aldosterone is responsible for the reabsorption of about 2% of filtered glomerular filtration rates. Sodium retention is also a response of the distal colon and sweat glands to aldosterone receptor
Adrenal gland
11367074
flow (eRPF). However, since the renal extraction ratio of PAH almost equals 1, then eRPF almost equals RPF. The renal extraction ratio of PAH in a normal individual is approximately 0.92, and thus not exactly 1.0. Thus, this method usually underestimates RPF by approximately 10%. This margin of error is generally acceptable considering the ease with which eRPF is measured. PAH clearance Para-aminohippurate (PAH) clearance is a method used in renal physiology to measure renal plasma flow, which is a measure of renal function. PAH is completely removed from blood that passes through the kidneys (PAH undergoes both glomerular filtration
PAH clearance
4517687
Renal artery The renal arteries normally arise off the left interior side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys. It has a radius of approximately 0.25 cm, 0.26 cm at the root. The measured mean diameter can differ depending on
Renal artery
5730816
device would allow for a patient to be treated twenty-four hours a day. With the development of miniature pumps, the hope of an effective wearable hemodialysis device has become realizable. Some patients already receive continuous peritoneal dialysis treatment which allows them to remain ambulatory. However, only a small portion of dialysis patients use peritoneal dialysis treatment because it requires large amounts of dialysate to be stored and disposed. A healthy individual's kidneys filter blood 24 hours/day, 168 hours/week compared to an individual with end-stage renal disease whose dialysis treatment plan is approximately 12 hours a week. The treatment results in
Artificial kidney
3047247
the time that urine has been collected. This mass equals the mass filtered at the glomerulus as nothing is added or removed in the nephron. Dividing this mass by the plasma concentration gives the volume of plasma which the mass must have originally come from, and thus the volume of plasma fluid that has entered Bowman's capsule within the aforementioned period of time. The GFR is typically recorded in units of "volume per time", e.g., milliliters per minute (mL/min). Compare to filtration fraction. There are several different techniques used to calculate or estimate the glomerular filtration rate (GFR or eGFR).
Renal function
16199833
and the better water solubility (even in cold water) of sinistrin compared to inulin. Like inulin the polymer sinistrin is not metabolized in human blood and passes the kidneys unchanged. Both, inulin and sinsitrin, are therefore frequently used for the diagnosis of kidney disorders. An important measure of kidney function is the glomerular filtration rate (GFR). GFR is the volume of fluid filtered from the renal (kidney) glomerular capillaries into the Bowman's capsule per time unit. To measure this parameter, a marker substance is injected into the blood stream, and its rate of excretion in urine is compared to the
Sinistrin
14545953
pregnancy, the woman might develop physiological hydronephrosis and hydroureter, which are normal. Progesterone causes vasodilatation and increased blood flow to the kidneys, and as a result glomerular filtration rate (GFR) commonly increases by 50%, returning to normal around 20 weeks postpartum. The increased GFR increases the excretion of protein, albumin, and glucose. The increased GFR leads to increased urinary output, which the woman may experience as increased urinary frequency. Progesterone also causes decreased motility of the ureters, which can lead to stasis of the urine and hence an increased risk of urinary tract infection. Pregnancy alters the vaginal microbiota with
Maternal physiological changes in pregnancy
12246938
mammals have longer and more deeply inset nephrons, as well as smaller and fewer cortical and juxtamedullary glomeruli (glomeruli being capillary networks where both fluid and waste are extracted from blood). This in turn leads to a smaller glomerular filtration rate, and on the whole, less water is transferred from the blood to the kidney. The kidneys of desert mammals are also better adapted at reabsorbing water from the tubular fluid: though there are fewer glomeruli, the xerocole has larger juxtamedullary glomeruli than cortical glomeruli (the former playing an important role in concentrating urine), whereas the opposite is true for
Xerocole
2323197
The secretion of aldosterone has a diurnal rhythm. Aldosterone is the primary of several endogenous members of the class of mineralocorticoids in humans. Deoxycorticosterone is another important member of this class. Aldosterone tends to promote Na and water retention, and lower plasma K concentration by the following mechanisms: Aldosterone is responsible for the reabsorption of about 2% of filtered sodium in the kidneys, which is nearly equal to the entire sodium content in human blood under normal glomerular filtration rates. Aldosterone, probably acting through mineralocorticoid receptors, may positively influence neurogenesis in the dentate gyrus. Steroid receptors are intracellular. The aldosterone
Aldosterone
18171779
restricting foods that contain phosphorus and potassium can lead to deficiencies in other important vitamins. In general, the following vitamins and minerals are supplemented in dialysis patients: Nutrition for patients on dialysis varies on an individual basis. It can be very confusing trying to determine which vitamins and minerals need to be supplemented and which do not so it is important for dialysis patients to speak with a doctor before making any changes to their nutritional plan. Kidney disease Kidney dialysis Vitamin and mineral supplementation for dialysis patients When healthy, the kidneys are responsible for the continuous filtration of blood
Vitamin and mineral supplementation for dialysis patients
6873134
body size. As food and saltwater are ingested, sodium and water absorption begins through the walls of the gut and into the extracellular fluid. Sodium is then circulated to the kidney, where the plasma undergoes filtration by the renal glomerulus. Although birds' kidneys tend to be larger in size, they are inefficient in producing concentrated urine that is significantly hyperosmotic to their blood plasma. This form of secretion would cause dehydration from water loss. Therefore, sodium and water are reabsorbed into the plasma by renal tubules. This increase in osmotic plasma levels causes extracellular fluid volume to increase, which triggers
American flamingo
662895
is reabsorbed as it passes through the nephron and the remaining 1% becomes urine. The urinary system is regulated by the endocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone. The urinary system is under influence of the circulatory system, nervous system, and endocrine system. Aldosterone plays a central role in regulating blood pressure through its effects on the kidney. It acts on the distal tubules and collecting ducts of the nephron and increases reabsorption of sodium from the glomerular filtrate. Reabsorption of sodium results in retention of water, which increases blood pressure and blood volume. Antidiuretic
Urinary system
7377389
Renal blood flow In the physiology of the kidney, renal blood flow (RBF) is the volume of blood delivered to the kidneys per unit time. In humans, the kidneys together receive roughly 25% of cardiac output, amounting to 1.1 L/min in a 70-kg adult male. RBF is closely related to renal plasma flow (RPF), which is the volume of blood plasma delivered to the kidneys per unit time. While the terms generally apply to arterial blood delivered to the kidneys, both RBF and RPF can be used to quantify the volume of venous blood exiting the kidneys per unit time.
Renal blood flow
3252120
valve and bypass procedures, emergency surgery, and preoperative intraaortic balloon pump are risk factors most strongly correlated with post-cardiopulmonary bypass acute kidney injury. Other well-known minor risk factors include: female gender, congestive heart failure, chronic obstructive pulmonary disease, insulin-requiring diabetes, and depressed left ventricular ejection fraction. "Prerenal" causes of AKI ("pre-renal azotemia") are those that decrease effective blood flow to the kidney and cause a decrease in the glomerular filtration rate (GFR). Both kidneys need to be affected as one kidney is still more than adequate for normal kidney function. Notable causes of prerenal AKI include low blood volume (e.g.,
Acute kidney injury
9865410
growth of the crystals, the diameter of the segments of the nephron, and the transit time in the nephron. All of these combined show more and more support for this theory. Nephrocalcinosis Nephrocalcinosis, once known as Albright's calcinosis after Fuller Albright, or Anderson-Carr kidneys, is a term originally used to describe deposition of calcium salts in the renal parenchyma due to hyperparathyroidism. The term nephrocalcinosis is used to describe the deposition of both calcium oxalate and calcium phosphate. It may cause acute kidney injury. It is now more commonly used to describe diffuse, fine, renal parenchymal calcification on radiology. It
Nephrocalcinosis
4245850
stenosis is longstanding and severe, the glomerular filtration rate in the affected kidneys never recovers and (prerenal) kidney failure is the result. Changes include: The diagnosis of renal artery stenosis can use many techniques to determine if the condition is present, a clinical prediction rule is available to guide diagnosis. Among the diagnostic techniques are: It is initially treated with medications, including diuretics, and medications for blood pressure control. When high-grade renal artery stenosis is documented and blood pressure cannot be controlled with medication, or if renal function deteriorates, surgery may be resorted to. The most commonly used procedure is
Renal artery stenosis
7519630
it extends over multiple body segments) projects into the coelom rather than into the proximal tip of the nephron. The glomerular filtrate flows directly into the coelom, or a dorsal compartment of the coelom known as the nephrocoel. In jawless fishes, the pronephric glomus projects into the pericardial cavity. Fluids are swept from the filtration cavity into the nephron through cilated funnels known as nephrostomes. These thin epithelial tubes are densely packed with cilia and have a distinct morpology to the other tubular epithelia of the kidney. Older anatomical texts describe the pronephros as condensing from nephrotomes, but modern visualization
Pronephros
4812753
to the arginine-vasopressin (AVP) containing vesicle membrane. This causes the fusion of the vesicle with the neuronal post synaptic membrane. Subsequent release of AVP into the posterior pituitary gland occurs, whereby vasopressin is secreted into the blood stream of the nearby capillaries. The macula densa region of the kidney's juxtaglomerular apparatus is another modulator of blood osmolality. The macula densa responds to changes in osmotic pressure through changes in the rate of sodium ion (Na) flow through the nephron. Decreased Na flow stimulates tubuloglomerular feedback to autoregulate, a signal (thought to be regulated by adenosine) sent to the nearby juxtaglomerular
Osmoreceptor
5106116
severe retardation of growth and hair development. In general, as the period of time between birth and inoculation decreases, less disease and mortality occurs. Post mortem lesions in mice show signs of hepatomegaly, splenomegaly, lymphaden opathy, and swollen or shrunken and pitted kidneys due to glomerulonephritis. Histological findings in persistently infected mice often show chronic glomerulonephritis. In these mice, and some hamsters, vasculitis and lymphocytic infiltrates in many organs and tissues including the liver, spleen, lung, kidneys, pancreas, blood vessels, meninges and brain are present. Pathogenesis occurs in the same manner in hamsters as in mice. Symptoms in hamsters are
Lymphocytic choriomeningitis
10047764
diuretics and thiazide diuretics decrease filtration fraction. Catecholamines (norepinephrine and epinephrine) increase filtration fraction by vasoconstriction of afferent and efferent arterioles, possibly through activation of alpha-1 adrenergic receptors. Severe haemorrhage will also result in an increased filtration fraction. Filtration fraction In renal physiology, the filtration fraction is the ratio of the glomerular filtration rate (GFR) to the renal plasma flow (RPF). Filtration Fraction, FF = GFR/RPF, or formula_1. 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
Filtration fraction