Each kidney has nearly one million tubular structures called nephrons. Each nephron consists of a filtering corpuscle called renal corpuscle or malphigian body and a renal tubule. The renal tubule opens into a longer tubule called the collecting duct. The renal corpuscle has a double walled cup shaped structure called the Bowman’s capsule. It encloses a ball of capillaries called the glomerulus.
The Bowman’s capsule and the Glomerulus together constitute the renal corpuscle. The endothelium of glomerulus has many pores called fenestrae.
The external parietal layer of the Bowman’s capsule is made up of simple squamous epithelium. The visceral layer is made of epithelial cells called podocytes. The podocytes end in foot processes which cling to the basement membrane of the glomerulus. The openings between the foot processes are called filtration slits.
The renal tubule continues further to form the proximal convoluted tubule, Henle’s loop and the distal convoluted tubule. The Henle’s loop has a thin descending limb and a thick ascending limb.
The distal convoluted tubule of many nephrons open into a collecting duct. The proximal and the distal convoluted tubule are situated in the cortical region whereas the Henle’s loop is situated in the medullary region of the kidney.
