Master Distal Tubule with Picmonic for Pre-Health

The distal tubule is regulated by many endocrine hormones that affect the reabsorption of solutes. These include aldosterone, increases the amount of sodium, and parathyroid hormone, that increases absorption of more calcium.

Aldosterone increases sodium reabsorption by up-regulating and activating sodium-potassium pumps.

Sodium is reabsorbed through active transport via the sodium-potassium ATPase pumps. These sodium-potassium pumps create the gradients necessary to absorb sodium through Na/Cl symport.

Water follows sodium concentration gradients through osmosis, flowing from areas of low sodium concentrations to high sodium concentrations. However, the early distal tubule is impermeable to water, preventing water from following sodium through osmosis in this part of the nephron.

The early distal tubule is impermeable to water, preventing water from following sodium through osmosis in this part of the nephron.

Parathyroid hormone increases calcium absorption in the distal tubule through a calcium-phosphorus regulation mechanism.

The distal tubule leads to the collecting duct system, which is the last part of the nephron. This is an important site of water reabsorption under the action of vasopressin or ADH, which increases the collecting duct's permeability to water.