Describe the process of renal tubular reabsorption of Na+ and H 2 O
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Answer:
Tubular reabsorption is the process that moves solutes and water out of the filtrate and back into your bloodstream. This process is known as reabsorption, because this is the second time they have been absorbed; the first time being when they were absorbed into the bloodstream from the digestive tract after a meal.
Sodium/potassium ATPase, a sodium pump (active transporter) located on the opposite side of the epithelial cell that takes care of this by moving three sodium ions out of the cell for reabsorption into the bloodstream, and pumping two potassium ions back into the cell.
Sodium/proton exchanger, which enables reabsorption of bicarbonate. Glucose, amino acids and other substances diffuse out of the epithelial cell down their concentration gradients on passive transporters and are then reabsorbed by the blood capillaries. By the time the filtrate has reached the mid part of the proximal tubule, 100% of the filtered glucose and amino acids have been reabsorbed, and large amounts of sodium, bicarbonate, phosphate, lactate, and citrate ions.