Muscular layers of the urinary bladder (400X)

The muscular layer, known as the detrusor muscle, consists of two layers of smooth muscle fibers that contract during urination, one longitudinal layer and one circular layer.

The outermost layer is the adventitia or serosa, depending on its location within the abdominal cavity.

Blood vessels and nerve endings are distributed throughout the bladder wall, contributing to its sensory and contractile functions.