This video (part 1 of 2) begins with filtration of blood at the glomerulus, and describes how substances are taken out of the nephron and put back into the blood (reabsorption). The parts of the nephron, such as the glomerulus, the proximalconvoluted tubule, the distal convoluted tubule, and the collecting ducts are colored and their roles in urine formation explained. I also explain the juxtaglomerular apparatus and its role in releasing erythropoietin and renin. www.sciencewithsusanna.com has diagrams, notes and practice questions.