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Unformatted text preview: can only reabsorb a limited amount (because they can become saturated) and the remainder will be excreted in the urine -- a hallmark of diabetes. As solutes are reabsorbed, water is also absorbed by osmosis and carries other solutes with it paracellularly in a process known as solvent drag. The unusually high osmotic pressure in the peritubular capillaries around the PCT and low BP also favors reabsorption of water into the blood. This "obligatory" reabsorption of water is necessary to reabsorb solutes and does not change significantly in response to environmental changes. The major mechanism for transport of water soluble solutes from the tubular fluid into the PCT epithelial cells is by secondary active transport. From the cells to the blood it is often facilitated diffusion. However, many other solutes move by solvent drag or transcytosis. Examine the figure below for details....
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This note was uploaded on 01/30/2012 for the course BSC BSC1085 taught by Professor Sharonsimpson during the Fall '10 term at Broward College.
- Fall '10