kidney

(redirected from chronic kidney failure)
Also found in: Dictionary, Thesaurus, Medical, Acronyms, Wikipedia.

kidney

1. either of two bean-shaped organs at the back of the abdominal cavity in man, one on each side of the spinal column. They maintain water and electrolyte balance and filter waste products from the blood, which are excreted as urine
2. the corresponding organ in other animals
www.kidney.org

Kidney

An organ involved with the elimination of water and waste products from the body. In vertebrates the kidneys are paired organs located close to the spine dorsally in the body cavity. They consist of a number of smaller functional units called urinary tubules or nephrons. The nephrons open to large ducts, the collecting ducts, which open into a ureter. The two ureters run backward to open into the cloaca or into a urinary bladder. In mammals, the kidneys are bean-shaped and found between the thorax and the pelvis. The number, structure, and function of the nephrons vary with evolution and, in certain significant ways, with the adaptation of the animals to their various habitats.

In its most primitive form, found only in invertebrates, the nephron has a funnel opening into the coelomic cavity followed by a urinary tubule leading to an excretory pore. In amphibians, some of the tubules have this funnel, but most of the tubules have a Bowman capsule (see illustration). In all higher vertebrates, the nephron has the Bowman capsule, which surrounds a tuft of capillary loops, called the glomerulus, constituting the closed end of the nephron. The inner epithelial wall of the Bowman capsule is in intimate contact with the endothelial wall of the capillaries. The wall of the capillaries, together with the inner wall of the Bowman capsule, forms a membrane ideally suited for filtration of the blood.

Nephron from frog kidney, dissected to show glomerulus within Bowman capsuleenlarge picture
Nephron from frog kidney, dissected to show glomerulus within Bowman capsule

The blood pressure in the capillaries of the glomerulus causes filtering of blood by forcing fluid, small molecules, and ions through the membrane into the lumen of Bowman's capsule. This filtrate contains some of the proteins and all of the smaller molecules in the blood. As the filtrate passes down through the tubule, the walls of the tubule extract those substances not destined for excretion and return them to the blood in adjacent capillaries. Many substances which are toxic to the organism are moved in the opposite direction from the blood into the tubules. The urine thus produced by each nephron is conveyed by the collecting duct and ureter to the cloaca or bladder from which it can be eliminated.

In all classes of vertebrates the renal arteries deliver blood to the glomeruli and through a second capillary net to the tubules. The major blood supply to the kidney tubules comes, however, from the renal portal vein, which is found in all vertebrates except mammals and cyclostomes. Waste products from the venous blood can thus be secreted directly into the urinary tubules. See Urinary system

kidney

[′kid·nē]
(anatomy)
Either of a pair of organs involved with the elimination of water and waste products from the body of vertebrates; in humans they are bean-shaped, about 5 inches (12.7 centimeters) long, and are located in the posterior part of the abdomen behind the peritoneum.
References in periodicals archive ?
Polycystic kidney disease in Persian cats (also seen in Scottish Folds, Himalayans and even some shorthair cats) can be a cause of genetic chronic kidney failure.
The prevalence of chronic kidney failure varied substantially by state/area.
Strategies for health-care providers to reduce chronic kidney failure * Control diabetes --Among persons with diabetes, those with glycated hemoglobin ([HbA1c) levels of <7% are less likely to have chronic kidney Failure (1).
Fresenius Medical Care is the world's largest, integrated provider of products and services for individuals undergoing dialysis because of chronic kidney failure, a condition that affects more than 1,400,000 individuals worldwide.
Fresenius Medical Care is the world's largest, integrated provider of products and services for individuals with chronic kidney failure, which affects more than 1,400,000 individuals worldwide.
works in partnership with nephrologists to acquire and operate outpatient treatment centers for persons suffering from chronic kidney failure, also known as End Stage Renal Disease.
Emanuele Gatti, Fresenius Medical Care Management Board Member responsible for Europe, Latin America, the Middle East and Africa: "The positive results of the new study support our efforts to provide innovative treatment methods such as hemodiafiltration to allow patients with chronic kidney failure to look confidently towards the future.

Full browser ?