Distal convoluted tubule

Kidney nephron

The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting duct system. It is partly responsible for the regulation of potassium, sodium, calcium, and pH.

Table of contents

1 Physiology 2 Histology 3 External links

Physiology

The DCT regulates pH by absorbing bicarbonate and secreting protons (H⁺) into the filtrate. Sodium and potassium levels are controlled by secreting K⁺ and absorbing Na⁺.

Sodium absorption by the distal tubule is mediated by the hormone aldosterone. Increased levels of aldosterone cause increased sodium absorption, and vice versa.

The DCT also participates in calcium regulation by absorbing Ca²⁺ in response to parathyroid hormone.

Histology

Histologically, cells of the DCT can be differentiated from cells of the proximal convoluted tubule since:

1. microvilli "brush border" is intact in DCT lumen
2. DCT cells are less eosinophilic than proximal cells
3. DCT cells have less cytoplasm
4. DCT cells have fewer nuclei

• Kidney function - Loyola University
• Calcium regulation - Cornell University