Distal convoluted tubule

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== 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

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

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

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

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.

Related Structures

• Proximal convoluted tubule
• Loop of Henle
• Collecting duct system
• Renal corpuscle

See Also

• Nephron
• Kidney function
• Electrolyte imbalance