Question

Distal Convoluted tubule Thick ascending limb of loop of Henle Na+ K+ Na+ Proximal tubule NaHCO3 Na+ CI- H2O Glucose Amino acids CH- CI- Ca2+ (PTH) Mg2+ Ca2+ Distal convoluted Proximal convoluted tubule +PTH) straight tubule K* Thin descending limb of loop of Henle H2O MOLE Mga Collecting tubule Cortex Naci (aldosterone Outer medulla 2C ascending limb scending HO (+ADH) Thin descending limb Collecting Diuretics Acetazolamide 2 Osmotic agents (mannitol) Loop agents (eg, furosemide) Thiazides 6 Aldosterone antagonists 6 ADH antagonists Adenosine Innor medulla Collecting Duct Na+ CI- K+ (secretion) H+ (secretion) 2 HO Thin ascending Loop of Henle Trevor's Pharmacology: Examination Board Review, 11th Ed. Source: AJ. Trevor B.G. Katzung, M. Kruidering Katung Copyright McGraw-Hal Education. All rights reserved

Guys please help, im confused with this slide. Are these ions the ones being reabsorbed???? for ex. proximal tubule. Also a question on diuretics list within the picture, what is their function??? to block the reabsorption of these ions???

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Answer 1

Isoosmotic(having the same osmotic pressure) reabsorption takes place in the Proximal convoluted tubule that is water, glucose, amino acids, potassium, chloride, and sodium are reabsorbed in PCT. But in Distal convoluted tubule and collecting duct, absorption of ions such as sodium, chloride, and calcium takes place. Similarly, in the thick ascending loop of Henle, sodium, potassium, chloride, calcium, and magnesium reabsorption takes place. Since Loop of Henle is impermeable to water, not water but ions are reabsorbed effortlessly.

Loop agents reabsorb 25% of sodium increasing potassium loss, and thiazide diuretics reabsorb about 5% of filtered sodium, inhibit NaCl reabsorption.

Acetazolamide inhibits NaHCO3 reabsorption and also reduces edema occurred as a result of heart failure or the effect of medications. Osmotic agents aid in taking out excess water and toxins from the body. Aldosterone antagonists block the reabsorption of sodium, leading to water loss. ADH antagonists absorb excess water from the collecting duct. Adenosine promotes reabsorption of glucose, ions and other metabolites.