Each of your kidneys is made up of about a million filtering units called nephrons. Each nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process: the glomerulus filters your blood, and the tubule returns needed substances to your blood and removes wastes. The blood is filtered by nephrons, the functional units of the kidney.Each nephron begins in a renal corpuscle, which is composed of a glomerulus enclosed in a Bowman's capsule. Aug 22, 2019 · Individual nephrons cannot be seen by the naked eye.The nephron is the basic structural and functional unit of the kidney. Each kidney has about 1 million nephrons. The walls of the nephron are made of a single layer of epithelial cells. Blood containing urea and metabolic waste products enters the kidney from the liver. The nephron consists of the renal corpuscle, the proximal convoluted tubule, the descending and ascending limbs of the loop of Henle, the distal convoluted tubule, and the collecting tubule. Each kidney is an aggregation of about a million nephrons. Nephron definition, the filtering and excretory unit of the kidney, consisting of the glomerulus and tubules. See more.