þvagblöðra

The þvagblöðra, or urinary bladder, is a hollow, muscular organ that collects and stores urine produced by the kidneys. It is located in the pelvis, behind the pubic bone. The bladder is roughly pear-shaped and can expand significantly to hold urine. Its walls are made of smooth muscle tissue that can contract to expel urine from the body.

Urine is transported from the kidneys to the bladder through two tubes called ureters. When the bladder is full, nerve signals are sent to the brain, creating the sensation of needing to urinate. Urination, also known as micturition, is the process of emptying the bladder. This occurs when the bladder muscles contract and the sphincter muscles at the base of the bladder relax, allowing urine to flow out through the urethra.

The capacity of the bladder varies among individuals but typically holds around 400 to 600 milliliters of urine. The inner lining of the bladder is made of transitional epithelium, which is specialized to stretch and contract. The bladder plays a crucial role in the urinary system, ensuring the efficient removal of waste products from the body.