what is the function of urethra

The urethra is a tube that allows urine to leave the body. It is part of the urinary system, which includes the kidneys, bladder, ureters, and urethra. In males, the urethra is also an essential component of the reproductive system, as it serves as a passage for semen during ejaculation. The male urethra is about 20 cm long and begins within the bladder wall and ends in the distal glans of the penis. In females, the urethra is much shorter, only about 4 cm long, and opens between the labia. The urethra is a dynamic fibromuscular tube that is lined with epithelial cells, which protect against the constant exposure to urine, seminal fluid, and the external environment. The submucosal layer is supportive due to its extensive vascular content, and the fibromuscular layer of cells is the outermost portion of the urethra and provides structure, propulsion, and tone to the urethra. Overall, the function of the urethra is to allow the passage of urine and semen out of the body.