The urethra is a canal in the form of a tube with two open ends that allows the urine stored in the bladder to be excreted outside the body. In common language, it is known as the outer urinary canal or the outer urinary tract. The inner surface of the urethra is covered by a layer called mucosa. The external opening of the urethra is called the meatus.
Urethra is found in both males and females. However, there are certain differences between the urethras of males and females.
The female urethra starts at the bladder neck and ends right above the vaginal opening. Its length is 3-4 cm. On the other hand, the male urethra starts at the bladder neck and ends at the tip of the penis. The male urethra is approximately 20 cm long. It allows both the excretion of urine and ejaculation.
The male urethra is comprised of three sections, which are prostatic, membranous, and spongy sections.
The prostatic urethra is the section of the urethra that traverses the prostate. Its length is approximately 3-4 cm. Canals that originate from the seminal vesicles and ejaculatory ducts of the prostate open to the prostatic urethra.
Membranous urethra is the shortest and narrowest section of the urethra. This section is surrounded by voluntary sphincter muscles that allow holding in urine.
Spongy urethra is the section that lies in the penis and it is the longest section of the urethra with a length of 15-16 cm. It is also known as the penile urethra. Ducts of the bulbourethral glands, which produce fluids that maintain the dampness of the urethra, open to the starting point of the penile urethra.