The urethral opening is the external opening of the urethra, a tube that carries urine from the bladder to the outside of the body. In humans, this opening is located at the tip of the penis in males and just above the vaginal opening in females. It plays a crucial role in the urinary system by allowing the expulsion of urine. In addition to urine, the urethral opening in males also serves as a passage for semen during ejaculation. The structure and function of the urethral opening can vary among different species, but its primary role remains consistent across mammals, including humans.