Notes: Each kidney is made of tube like structures called nephrons (renal tubules). A nephron is the structural and functional unit of the kidney. The cup-shaped upper end called Bowman’s capsule, has a network of capillaries within it called glomerulus. Glomerulus is a knot of capillaries formed from the artery which brings blood containing wastes and excess of water to the kidney. Bowman’s capsule leads into a tubular structure.