The urethra is a tubular connection responsible for the transport of urine from the bladder to the outside of the body. It is the body’s exit tube for liquid wastes.


Mucous membranes create the inner lining of the tube, and it is generally surrounded by a muscular layer. The smooth muscle fibers direct longitudinally. Within the wall of the urethra, the highly specialized urethra glands coat the urethral canal with a constant secretion of mucous.

The urethra is encompassed by two separate urethral sphincter muscles. The internal urethral sphincter muscle is created by involuntary smooth muscles while the lower voluntary muscles create the external sphincter muscles. The internal sphincter is created by the detrusor muscle.

In the female body, the urethra is approximately 4 centimeters long and leads out of the body via urethral orifice. In the female body, the urethral orifice is located in the vestibule in the labia minora.

This can be found located in between the clitoris and the vaginal orifice. In the female body the urethra’s only function is to transport urine out of the body.


Female Urethra
Image: Female Urethra

In the male body, the urethra not only excretes fluid wastes but is also part of the reproductive system. Rather than the straight tube found in the female body, the male urethra is shaped like a S to follow the line of the penis. It is approximately 20 centimeters long. The male urethra can be segregated into three various portions, the spongy portion, the prostatic portion, and the membranous portion. The proximal portion, which is also the prostatic portion, is only about 2.5 cm long and passes along the neck of the urinary bladder through the prostate gland. This section is designed to accept the drainage from the tiny ducts within the prostate and is equipped with two ejaculatory tubes.


Male Urethra
Image: Male Urethra
The membranous section is the shortest, at only .5 centimeter. This section passes through the proximal section of the penis and all the way through the urogential diaphragm. This is also where the external urethral sphincter muscle is positioned. The longest section is about 15 centimeters long and is known as the spongy part. It leads from the outer edge of the urogential diaphragm to the glans of the penis, where the external orifice is located. This section is encased in erectile tissue in the corpus spongiosum of the penis. The spongy part accepts attachment from the reproductive ducts of the bulbourethral glands.

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