Anatomical Location
The DCT is located in the renal cortex. It originates from the thick ascending limb of the loop of Henle and terminates as it joins the collecting duct system. The DCT is shorter and less convoluted than the
Proximal Convoluted Tubule (PCT).
Histological Features
The epithelial cells lining the DCT are characterized by a cuboidal shape, with fewer microvilli compared to those in the PCT. The cells have a prominent nucleus and relatively sparse cytoplasm. The presence of
basal infoldings is notable, which are involved in ion transport.
Functions of the DCT
The DCT is primarily involved in the fine-tuning of filtrate composition. Key functions include:Regulation Mechanisms
The activity of the DCT is tightly regulated by hormones and the body's needs.
Aldosterone plays a significant role in sodium and potassium balance.
Anti-diuretic hormone (ADH) can also affect the DCT indirectly by influencing water reabsorption in the collecting ducts.
Clinical Relevance
Disorders associated with the DCT include
Bartter syndrome, which involves defects in salt reabsorption, leading to imbalances in electrolytes.
Hyperaldosteronism can also affect the DCT, causing excessive sodium reabsorption and potassium loss.
Histological Identification
Under the microscope, the DCT can be distinguished from the PCT by observing the smaller size, lack of brush border, and the presence of more distinct cell boundaries. The lumen of the DCT appears clearer due to fewer microvilli.Conclusion
The DCT is an integral part of the nephron, contributing significantly to the regulation of electrolytes and acid-base balance. Understanding its structure and function is crucial for comprehending various renal pathologies and their treatments.
