Kidneys are reddish brown in colour, bean shaped, situated between the last thoracic and third lumbar vertebra level close to the dorsal inner wall of the abdominal cavity.

Towards the centre of the inner side of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter.

Inside the kidney, there are an outer cortex that extends in between the renal columns called Columns of Bertini and an inner medulla divided into medullary pyramids projecting into the calyx.

Each kidney has structures called nephrons which are the structural and functional units having two parts – the glomerulus and the renal tubule.

The renal tubule starts with a cup-like structure called Bowman’s capsule, by the glomerulus is enclosed and together they are called the renal corpuscle.

The tubule continues to form proximal convoluted tubule (PCT) followed by a hairpin shaped Henle’s loop having a descending and an ascending limb.

The ascending limb continues as another highly coiled tubular structure called distal convoluted tubule (DCT). The DCTs open into a tube called collecting duct.