what layer of the bladder contracts during urination
In men, the urethra is longer and is encircled by the prostate, which is a gland that is part of the reproductive system. Urination occurs when the urinary sphincter muscle relaxes and the bladder muscle contracts to expel the urine. The bladder consists of three layers. The inner lining layer of the bladder, called the mucosa, is formed by a type of cell called transitional cell. The next layer, the lamina propria, provides support to the mucosa. The third layer is the bladder muscle itself.