What is the definition or description of: bladder?

Urine storage & void: The bladder is a muscular organ in the pelvis that accepts urine from the kidneys, stores the urine at low pressure, & expels the urine during voluntary voiding. Though seemingly a simple reservoir, the bladder is a complex organ intricately connected with the brain and spinal cord with sensory, motor, and autonomic circuits. The muscular layer that contracts during voids is called the detrusor.