The capillaries of glomerulus are enclosed by a cup-like structure called Bowman’s capsule. This structure extends to form highly coiled tubules called PCT. PCT continues to form the loop of Henle which ascends to DCT, which in turn opens into the collecting duct.
The major function of tubules is reabsorption and the process can either be active or passive. In addition, secretions by tubules help in the urine formation without affecting the electrolyte balance of the body.