Tubular secretion is crucial as it helps in the maintenance of ionic balance in the body fluids.

Proximal Convoluted Tubule has simple cuboidal epithelium that increases the surface area for reabsorption. It also maintains the pH and ionic balance of the body fluids by selective secretion.

Distal Convoluted Tubule is where conditional reabsorption of sodium ions and water takes place. It is also responsible for selectively secreting hydrogen and potassium ion to maintain the ionic balance and pH.

Collecting Duct: From this long duct, large amounts of water could be reabsorbed to produce concentrated urine. It plays a role in the maintenance of pH and ionic balance of blood by the selective secretion of ions as well as maintain osmolarity.