Virtsanjohtimien

Virtsanjohtimien, known in English as ureters, are two narrow, muscular tubes that connect the kidneys to the bladder. Each ureter is about 25 to 30 centimeters long and approximately 3 to 5 millimeters in diameter. They are responsible for transporting urine from the renal pelvis of each kidney down to the urinary bladder.

The walls of the ureters are composed of three layers: an inner lining of transitional epithelium, a middle muscular layer, and an outer adventitial layer. The muscular layer plays a crucial role in urine transport through a process called peristalsis. Rhythmic contractions of these muscles propel urine downward, even against gravity.

Urine is produced by the kidneys and collects in the renal pelvis, the funnel-shaped structure at the top of the ureter. From there, it enters the ureter and travels to the bladder. The flow of urine is generally unidirectional, prevented from flowing back towards the kidneys by a valve-like mechanism where the ureters enter the bladder.

Problems with the ureters can include blockages, infections, and stones. Ureteral stones, or kidney stones that have moved from the kidney, can cause severe pain as they attempt to pass through the narrow tubes. Blockages can also be caused by external compression or strictures. Inflammation of the ureters is known as ureteritis. The function of the ureters is vital for the efficient removal of waste products from the body.