8. Loop of Henle Simplified | Countercurrent Mechanism | USMLE Step 1

𝐒𝐮𝐛𝐬𝐜𝐫𝐢𝐛𝐞 𝗙𝐨𝐫 𝗠𝐨𝐫𝐞 𝗜𝐧𝐟𝐨𝐫𝐦𝐚𝐭𝐢𝐨𝐧 𝐨𝐧 𝗛𝐞𝐚𝐥𝐭𝐡 👩‍⚕‍ 𝐚𝐧𝐝 𝗠𝐞𝐝𝐢𝐜𝐢𝐧𝐞💉🩺💊 📌𝗜𝗻𝘀𝘁𝗮𝗴𝗿𝗮𝗺 : https://www.instagram.com/clinical.learning/ Loop of Henle Simplified | Countercurrent Mechanism | USMLE Step 1 The Loop of Henle is a U-shaped segment of the nephron that dips into the renal medulla and plays a crucial role in urine concentration and water conservation via the countercurrent multiplier mechanism 🌀💧. It consists of three segments: the thin descending limb, which is highly permeable to water but impermeable to solutes, allowing water to passively exit into the hyperosmotic medullary interstitium — concentrating the tubular fluid. The thin ascending limb is impermeable to water but allows passive Na⁺ and Cl⁻ reabsorption. The thick ascending limb (TAL) actively reabsorbs Na⁺, K⁺, and 2Cl⁻ via the NKCC2 cotransporter, but remains impermeable to water, diluting the tubular fluid — hence it is also called the diluting segment. This active solute transport sets up the osmotic gradient essential for water reabsorption in the collecting duct under the influence of ADH. The Loop of Henle is also highly sensitive to loop diuretics (e.g., furosemide), which inhibit the NKCC2 channel, leading to natriuresis and diuresis. Its proper function is critical for maintaining medullary hypertonicity, plasma osmolality, and overall fluid and electrolyte balance, making it a cornerstone of renal physiology 🔬🩺. #LoopOfHenle #RenalPhysiology #CountercurrentMechanism #USMLEStep1 #NEETPG #FMGEprep #DrSreeTeja #NKCC2 #Furosemide #UrineConcentration #WaterBalance #MBBSnotes #Nephron #HighYieldMedicine #MedicalYouTube #ShortsForDoctors