Within the nephron (the functional unit of the kidneys), filtration occurs in the glomerolus. The filtered fluid is called filtrate. Reabsorption of filtrate occurs in a few places within the nephron, however, the majority of reabsorption takes place in the proximal convoluted tube. It is important to mention that additional reabsorption occurs in the Loop of Henle, distal convoluted tube, and the collecting ducts as well.