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The collecting duct system of the kidney consists of a series of tubules and ducts that physically connect nephrons to a minor calyx or directly to the renal pelvis.The collecting duct participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and vasopressin (antidiuretic hormone).
The collecting duct system begins in the renal cortex and extends deep into the medulla. As the urine travels down the collecting duct system, it passes by the medullary interstitium which has a high sodium concentration as a result of the loop of Henle's countercurrent multiplier system. [1]: 67
The last step in the processing of the ultrafiltrate is excretion: the ultrafiltrate passes out of the nephron and travels through a tube called the collecting duct, which is part of the collecting duct system, and then to the ureters where it is renamed urine. In addition to transporting the ultrafiltrate, the collecting duct also takes part ...
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.
The medulla is divided into outer and inner regions. The outer region consists of short loops of Henle and collecting ducts, and the inner region consists of long loops of Henle and collecting ducts. [28] After passing through the loop of Henle, the fluid becomes hypertonic relative to the blood plasma. [78] The renal portal system is absent in ...
The maintenance of this concentration gradient is one of the components responsible for the kidney's ability to produce concentrated urine. On the descending portion of the vasa recta, sodium, chloride and urea are reabsorbed into the blood, while water is secreted.
Simple cuboidal epithelium is a type of epithelium that consists of a single layer of cuboidal (cube-like) cells which have large, spherical and central nuclei.. Simple cuboidal epithelium is found on the surface of ovaries, the lining of nephrons, the walls of the renal tubules, parts of the eye and thyroid, and in salivary glands.
Blood exits the glomerular capillaries by an efferent arteriole instead of a venule, as is seen in the majority of capillary systems (Fig. 4). [ 3 ] This provides tighter control over the blood flow through the glomerulus, since arterioles dilate and constrict more readily than venules, owing to their thick circular smooth muscle layer ( tunica ...