How Kidneys Produce Urine Part 3

A portion of the blood that is still in the glomerulus flows into the capillaries. The capillaries surround the convoluted tubule. As the tubular fluid flows through the tubule, substances needed by the body are absorbed by the cells of the tubule wall. These substances, which include amino acids, glucose, and about 99 percent of water, then rejoin the blood in the capillaries. The capillaries return the blood to the heart by way of the renal vein.