<prompt> All are true about the trigone on the base of the urinary bladder, except ?Mucosa is loosely associated to the underlying musculatureMucosa is smoothIt is lined by transitional epitheliumIt is derived from the absorbed pa of the mesonephric duct  <response>: Trigone of the urinary bladder is a small triangular area located at the base of the bladder with apex towards the lower side. The mucosa is firmly attached to the underlying musculature giving it a smooth texture. 