Distal convoluted tubule

Kidney_nephron.png

== Distal Convoluted Tubule ==

The distal convoluted tubule (DCT) is a portion of the kidney nephron between the loop of Henle and the collecting duct system. It plays a crucial role in the regulation of electrolytes and pH balance in the body.

Structure[edit | edit source]

The distal convoluted tubule is lined with a single layer of cuboidal epithelial cells. These cells have fewer microvilli compared to the proximal convoluted tubule, making the lumen of the DCT appear clearer under a microscope. The DCT is located in the renal cortex.

Function[edit | edit source]

The primary functions of the distal convoluted tubule include:

**Reabsorption of Ions**: The DCT reabsorbs sodium and chloride ions through active transport mechanisms. This process is regulated by the hormone aldosterone.
**Calcium Regulation**: The DCT plays a role in calcium homeostasis, influenced by the hormone parathyroid hormone (PTH).
**Acid-Base Balance**: The DCT helps in maintaining the body's acid-base balance by secreting hydrogen ions and reabsorbing bicarbonate.

Hormonal Regulation[edit | edit source]

The activity of the distal convoluted tubule is regulated by several hormones:

**Aldosterone**: Increases sodium reabsorption and potassium secretion.
**Parathyroid Hormone (PTH)**: Increases calcium reabsorption.
**Antidiuretic Hormone (ADH)**: Although primarily acting on the collecting duct, ADH can also influence water reabsorption in the DCT.

Clinical Significance[edit | edit source]

Dysfunction in the distal convoluted tubule can lead to various medical conditions, including:

**Hyperkalemia**: Elevated levels of potassium in the blood due to impaired potassium secretion.
**Hypocalcemia**: Low levels of calcium in the blood due to impaired calcium reabsorption.
**Metabolic acidosis**: A condition where the body produces excessive acid or the kidneys are not removing enough acid from the body.