munuaistiehyistä

Munuaistiehyet, also known as renal tubules, are microscopic, coiled tubes within the nephrons of the kidney. They play a critical role in processing the filtrate that originates in the glomerulus. The primary function of the renal tubules is reabsorption and secretion, processes essential for regulating the body's water and electrolyte balance, and for removing waste products from the blood.

The tubular system begins with the proximal convoluted tubule, where a large proportion of water, glucose, amino acids, and ions are reabsorbed back into the bloodstream. Following this is the loop of Henle, a U-shaped structure that descends into the medulla and then ascends back towards the cortex. The loop of Henle is crucial for establishing a concentration gradient in the renal medulla, which is vital for the kidney's ability to concentrate urine.

The distal convoluted tubule follows the loop of Henle. Here, further reabsorption and secretion occur, primarily influenced by hormones such as aldosterone and antidiuretic hormone (ADH). These hormones regulate sodium and water reabsorption, respectively. Finally, the distal convoluted tubule leads into the collecting duct, which receives fluid from several nephrons. The collecting ducts further refine the urine, with their permeability to water being controlled by ADH, allowing for fine-tuning of the final urine concentration before it is transported to the renal pelvis. Diseases affecting the renal tubules can lead to a variety of kidney disorders, impacting the body's ability to maintain homeostasis.