Seminal vesicles

Seminal vesicles are a pair of glands found in male mammals that produce a significant proportion of the fluid that ultimately becomes semen. They are located posterior to the urinary bladder and above the prostate gland. The seminal vesicles secrete a fluid that is rich in fructose, which provides the sperm with a source of energy that aids in their motility. The fluid also contains prostaglandins, which assist in the successful fertilization of the ovum by the sperm.

Anatomy

The seminal vesicles are a pair of tubular structures approximately 5 cm in length, though this can vary. They are located within the pelvic cavity, posterior to the urinary bladder and above the prostate gland. Each seminal vesicle consists of a single, coiled tube that is lined with secretory cells and surrounded by smooth muscle.

Function

The primary function of the seminal vesicles is the production of seminal fluid. This fluid makes up approximately 70% of the total volume of semen. The fluid produced by the seminal vesicles is rich in fructose, which provides the sperm with a source of energy that aids in their motility. The fluid also contains prostaglandins, which assist in the successful fertilization of the ovum by the sperm.

In addition to providing energy and aiding in fertilization, the seminal fluid also helps to protect the sperm from the acidic environment of the female reproductive tract. The fluid has an alkaline pH, which helps to neutralize the acidity of the female reproductive tract and increase the lifespan of the sperm.

Clinical significance

Diseases and conditions that can affect the seminal vesicles include vesiculitis, which is inflammation of the seminal vesicles, and cancer. Vesiculitis can cause pain and fertility problems, while cancer of the seminal vesicles is rare but can be serious.

See also

• Male reproductive system
• Prostate gland
• Semen
• Sperm