Water Reabsorption in the Renal Tubule | Aquaporin, Water Transport, Mechanism of Water Reabsorption

📝 All videos on Renal Physiology: https://www.nonstopneuron.com/post/ph... 🌐 Explore our entire animation video library: https://www.nonstopneuron.com/ ● Follow me at: • Instagram:   / nonstopneuron   • Facebook:   / nonstopneuron   Water Reabsorption in the Renal Tubule: Water is filtered freely at the glomerulus. So osmolarity of filtrate is 300. The proximal tubule reabsorbs 65% of filtered water. The driving force for this reabsorption is the active reabsorption of solutes, which creates an osmotic gradient. The mechanisms are paracellular movement, as well as transcellular route, involving aquaporin 1. The osmolarity of the fluid at the end of the proximal tubule is the same 300 miliosmoles per liter. The thin descending limb reabsorbs 20% of filtered water. The driving force is medullary hyperosmolarity. And the mechanism is a transcellular movement, involving aquaporin 1. The osmolarity here gets as high as 600 to 1200. The ascending limb, and early distal tubule, do not reabsorb water. However, reabsorption of solutes here, makes the fluid hypoosmolar, with osmolarity getting as low as 100. The reabsorption from the late distal tubule, and collecting duct, occurs by transcellular route, involving aquaporin 2&3. The extent of this reabsorption depends on bodies needs. Normally, about 14% is reabsorbed, and 1% is excreted. So normal urine output is about 1.5 liters per day. When the body needs to conserve water, the vasopressin increases the reabsorption. In extreme cases, the excretion can decrease up to 0.3%, or 0.5 liters per day. The osmolarity in such cases, can get as high as 1200. On the other hand, when the body has access water, lack of vasopressin, decreases the reabsorption. In heavy water load, only 5% is reabsorbed. So up to 10%, or 20 liters of water is excreted. The osmolarity in such cases, can get as low as 30 miliosmoles per liter. Chapters: 00:00 Introduction 00:18 Basic Points 01:39 Percentage of Water Reabsorbed in Different Segments 03:08 at Glomerulus (Filtration) 03:28 at Proximal Tubule: 65% 04:18 at thin Descending Limb: 20% 04:57 at Impermeable Segments: 0% 05:37 at Collecting Duct: 1% 06:20 Regulation by Vasopressin 07:52 Summary 10:14 Bonus Point Dr Vipul Navadiya Nonstop Neuron Medical Animation Medical Animation Videos Physiology #physiology #humanphysiology DISCLAIMER: This video is for education purposes only. Although every effort is made to ensure the accuracy of the material, viewers should refer to the appropriate regulatory body/authorized websites, guidelines, and other suitable sources of information as deemed relevant and applicable. In view of the possibility of human error or changes in medical science, any person or organization involved in the preparation of this work accepts no responsibility for any errors or omissions, or results obtained from the use of information in this video.