Loop diuretics acts on?
Correct Answer: Thick ascending limb
Description: ANSWER: (B) Ascending limbREF: Goodman Gillman pharmacology 11th ed page 482See APPENDIX-14 below for "RENAL PHYSIOLOGY"Loop diuretics inhibit the activity of the Na+-- K+--2C1- symporter in the TAL (thick ascending limb) of the loop of Henle, hence, their designation as loop diuretics.DIURETICSITE OF ACTIONMECHANISM OF ACTIONCarbonic anhy- drase inhibitorsProximal convovulted tubules* Inhibit both the membrane-bound and cytoplasmic forms of carbonic anhy- draseLoop diureticsAscending limb of loop of henle* Na-K-2C1 Transporter inhibitor* Weak carbonic anhydrase inhibitor* Redistribution of renal blood flowEthacrinic acidAscending limb of loop of henle* Na-K-2C1 Transporter inhibitorThiazideEarly distal tubule* Na-Ci symporter inhibitorSpirinolactoneInterstitial side of distal tubule or collecting duct* Binds to intracellular mineralocorticoid receptorTriamterene and amiliorideLuminal side of distal tubule or collecting duct* Blocks luminal Na channels APPENDIX - 14 Renal Physiology:SubstanceDescriptionProximal TubuleLoop of HenleDistal TubuleCollectingDuctGlucoseIf glucose is not reabsorbed by the kidney, it appears in the urine, in a condition known as glucosuria. This is associated with diabetes mellitus.Reabsorption (almost 100%) via sodium- glucose transport proteins (apical) and GLUT (basolateral). Oligopeptides, proteins, and amino acidsAll are reabsorbed nearly completely.reabsorption UreaRegulation of osmolality. Varies with ADHreabsorption (50%) via passive transportsecretion reabsorption in medullary collecting ductsSodiumUses Na-H antiport, Na-glucose symport. sodium ion channels {minor}reabsorption (65%, isosmotic)reabsorption (25%o, thick ascending, Na-K-2C1 symporter)reabsorption (5%, sodium- chloride symporter)reabsorption (5%, principal cells),stimulated byaldosterone via ENaCChlorideUsually follows sodium. Active (transcellular) and passive (paracellular)reabsorptionreabsorption (thin ascending, thick ascending,Na-K-2C1symporter)reabsorption(sodium-chloridesymporter) WaterUses aquaporin water channels. See also diuretic.absorbed osmotically along w'ith solutesreabsorption(descending) reabsorption (regulated by ADH, via arginine vasopressin receptor 2)BicarbonateHelps maintain acid- base balance.Reabsorption (80-90%)reabsorption(thickascending) reabsorption (intercalated cells, via band 3 and pendrin)ProtonsUses vacuolar H+ATPase secretion(intercalatedcells)PotassiumVaries upon dietary needs.Reabsorption (65%)reabsorption (20%, thick ascending, Na-K-2C1 symporter) secretion (common, via Na+/K+- ATPase, increased by aldosterone), or reabsorption (rare, hydrogen potassium ATPase)CalciumUses calcium ATPase,sodium-calciumexchangerreabsorptionreabsorption (thick ascending) via passive transport MagnesiumCalcium and magnesium compete, and an excess of one can lead to excretion of the other.reabsorptionreabsorption(thickascending)reabsorption PhosphateExcreted as titratable acid.Reabsorption (85%) via sodium/phosphate cotransporter. Inhibited by parathyroid hormone. Carboxylate Reabsorption (100%) via carboxylate transporters.
Category:
Pharmacology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now