What is the membrane of a nephron?

Nephrons are the basic functional unit of the kidneys. They take in blood through an afferent arteriole and filter it inside the Bowman's capsule in a series of capillaries called glomeruli. It is the walls of the glomeruli that contain the membrane, more accurately called semi-permeable membrane, that removed the serum from the blood to produce the filtrate that will eventually become urine.