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This illustration demonstrates the normal kidney physiology, including the Proximal Convoluted Tubule (PCT), Loop of Henle, and Distal Convoluted Tubule (DCT). It also includes illustrations showing where some types of diuretics act, and what they do. Renal physiology (Latin renes, "kidneys") is the study of the physiology of the kidney.
Each kidney, with its adrenal gland is surrounded by two layers of fat: the perirenal fat present between renal fascia and renal capsule and pararenal fat superior to the renal fascia. The human kidney is a bean-shaped structure with a convex and a concave border. [14]
The mesonephros persists and form the permanent kidneys in fish and amphibians, but in reptiles, birds, and mammals, it atrophies and for the most part disappears rapidly as the permanent kidney (metanephros) develops beginning during the sixth or seventh week, so that by the beginning of the fifth month only the ducts and a few of the tubules ...
Unlike mammals, the kidneys of reptiles do not have a clear distinction between cortex and medulla. [43] The kidneys lack the loop of Henle, have fewer nephrons (from about 3,000 to 30,000), and cannot produce hypertonic urine. [3] [21] Nitrogenous waste products excreted by the kidneys may include uric acid, urea and ammonia. [55]
The kidneys are located behind the peritoneum, in the retroperitoneum, outside the abdominal cavity. The viscera are also covered by visceral peritoneum . Between the visceral and parietal peritoneum is the peritoneal cavity , which is a potential space. [ 1 ]
The development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the archinephros, pronephros, mesonephros, and metanephros. [1] The pronephros is the most immature form of kidney, while the metanephros is most developed. The metanephros persists as the definitive adult kidney.
The unipapillary kidney with a single renal pyramid is the simplest type of kidney in mammals, from which the more structurally complex kidneys are believed to have evolved. [ 17 ] [ 6 ] [ 18 ] Differences in kidney structure are the result of adaptations during evolution to variations in body mass and habitats (in particular, aridity ) between ...
Different regions of the gut tube are initiated by retinoic acid (RA) from the pharynx to the colon. This RA causes transcription factors to be expressed in different regions of the gut tube. Thus, SOX2 specifies the esophagus and stomach; PDX1 specifies the duodenum; CDXC specifies the small intestine; CDXA specifies the large intestine and ...