Histology, Bladder

The urinary bladder is a sac that serves as a reservoir for urine. The urine formed by the kidneys' nephrons is transported to the urinary bladder for storage before it gets expelled through the urethra. The urinary bladder is located in the extraperitoneal space of the pelvis behind the pubic bones and extends into the abdomen when filled with urine. The bladder is divided into two main parts, each with its anatomical, histological, and functional features. Above the ureteric orifices, the upper part is composed of the apex and body, while the lower part consists of the fundus, trigone, and neck. The capacity of the bladder is about 500 mL in healthy individuals. See Image. Urinary Bladder, Vertical Section of Bladder Wall.

As the bladder fills, it stretches, simulating afferent signals. Efferent signals result in the bladder musculature's contraction and the subsequent urethral sphincter's relaxation. In addition to mechanoreceptors, various psychological factors like stress, sense of physical surroundings, and emotional status play a crucial role in the timing and setting of micturition. This section describes the detailed microscopic structure of the urinary bladder wall.