انت هنا الان : شبكة جامعة بابل > موقع الكلية > نظام التعليم الالكتروني > مشاهدة المحاضرة
الكلية كلية طب حمورابي
القسم الكلية ذات القسم الواحد
المرحلة 1
أستاذ المادة شهلاء خزعل عبد محمد جابك
04/03/2019 03:24:33
The kidneys must excrete an isotonic fluid in order for the osmotic balance of the extracellular fluid to be maintained. This means that water itself cannot simply be removed on its own, and must be excreted with other solutes to maintain this osmolarity. The water reabsorption at the kidneys is controlled by, mainly, the movement of sodium (and subsequently chloride) ions out of the nephron, such that water will follow. 67% of the reabsorption happens at the PCT and 25% at the loop of Henle. The rest is reabsorbed in a tightly regulated manner in the remaining nephron. ? Before talking about the specifics regarding sodium reabsorption, it is worth mentioning the role the GFR plays in sodium reabsorption. When the GFR changes, there will be a subsequent change in the concentration of sodium in the filtrate and the PCT will still reabsorb 67% of this. This means that the remaining sodium can be reabsorbed along the rest of the nephron. ? Proximal Convoluted Tubule The PCT is mainly involved in the reabsorption of sodium ions, chloride ions, water, and glucose from the tubular lumen. It can be divided into early (S1) and late (S2 and S3) proximal convoluted tubule which have different apical transporters. · The early PCT has a Na+-K+-ATPase on the basolateral surface, removing sodium ions from the intracellular fluid. The sodium ion electrochemical gradient produced as a consequence allows sodium to move into the cell, and is couple to H+ ion movement via the NHE and glucose symporters. Water and chloride ions will subsequently diffuse into from the nephron lumen into the extracellular fluid at the cellular junctions (paracellular route), to maintain the electrochemical, isosmotic balance. · The distal PCT most of the organic molecules and HCO3- ions have been removed. There is the Na+-K+-ATPase on the basolateral surface still and sodium reabsorption is now mainly coupled to H+ ions via the NHE. Chloride ions move across actively now in exchange for other negatively charged compounds, maintaining electrochemical neutrality in the ECF. The solutes
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
|