Tubular Secretion - Formation of Urine

 TUBULAR SECRETION 

This mechanism also changes the composition of urine. In tubular secretion, substances are actively secreted from the blood in the peritubular capillaries into the filtrate in the renal tubules. Waste products, such as ammonia and some creatinine, and the meta-bolic products of medications may be secreted into the filtrate to be eliminated in urine. Hydrogen ions (H+) may be secreted by the tubule cells to help maintain the normal pH of blood.

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