Seminal Vesicles: Anatomy, Function and Medical Conditions

Chart depicting the seminal vesicles and other components of the male reproductive anatomy.

What Are The Seminal Vesicles?

The seminal vesicles (also called seminal glands or vesicular glands) are two sac-like glands located in a man’s pelvis that are responsible for the production of the fluids that make up semen.

This article will discuss the anatomy and function of the seminal vesicles, as well as related health conditions and tips for keeping seminal vesicles healthy.

Anatomy and Function

The seminal vesicles are situated above the prostate gland, and beneath the bladder. Each seminal vesicle is made of a coiled tube from which a number of pouch-like receptacles stem from.

These tubes are composed of three separate layers:

  • The outer layer is composed of connective tissue
  • The middle layer is composed of smooth muscle tissue
  • The inner-most layer is composed of specialized cells that produce seminal vesicle fluid

The vas deferens and a portion of the seminal vesicles combine to form the ejaculatory duct. This duct empties into the urethra near the prostate gland. During ejaculation, strong contractions produced by the seminal vesicle’s smooth muscle layer push seminal vesicle fluid into the ejaculatory ducts and urethra to be released in the semen.

The seminal vesicles’ primary function is producing and storing the fluid that ultimately becomes semen. Approximately 70% of the semen released during ejaculation is made from this fluid.

The seminal vesicle fluid creates an environment which is vital for the sperm’s survival and ability to function properly. The seminal vesicle fluid is composed primarily of the following:

  • Fructose, a form of sugar that provides sperm cells with nutrients
  • Alkaline fluid that helps keep sperm alive in the vagina’s acidic environment
  • Proteins, including semenogelin, which creates a gel-like barrier around sperm for protection.
  • Potassium and phosphorus, which aid in sperm motility.
  • Prostaglandins, which are hormones that help prevent the female immune system from seeing sperm as an invader.

Health Conditions Involving The Seminal Vesicles

Although generally rare, there are a number of conditions that can potentially affect the seminal vessels.

Infection and Abscess

Infection can occur when bacteria are present in the seminal vessels. This can happen as a result of an infection involving the prostate gland or urethra. Typically, antibiotics are used to treat an infection of the seminal vesicles.

Sometimes an infection may lead to an abscess, which is the formation of a pocket of pus. If this occurs, the abscess might need to be drained.

Cysts

Seminal vesicle cysts (fluid-filled sacs) frequently occur without any noticeable signs or symptoms being present. Cysts can be present at birth or they can develop as a results of scarring due to an infection or previous prostate surgery.

A procedure using laparoscopic surgery may be used to remove the cyst, depending on its size.

Seminal Vesicle Stones

It is extremely rare for stones to form in the seminal vessels. Stones are thought to occur because of structural abnormalities or inflammation in the seminal vesicles. Stone formation may also be caused by urine leaking back into the ejaculatory duct.

It is recommended to have seminal vesicle stones removed, especially if they are large or if there are multiple stones present. This can be done with surgery using an laparoscope or endoscope.

Seminal Vesicle Cancer

It is exceedingly rare for cancer to develop in the seminal vesicles. There have only been 48 cases of seminal vesicle cancer documented in the US and Europe since the year 2000. The cause of cancer in seminal vesicles is currently unknown.

A number of cancers that affect the seminal veins occur as a result of cancer spreading from elsewhere in the body. This most commonly occurs with prostate cancer, due to the prostate’s proximity to the seminal vesicles.

Signs and Symptoms of Seminal Vesicle Conditions

Conditions involving the seminal vesicles can often be associated with the following signs:

  • Pain or discomfort during ejaculation
  • Pain or discomfort in the abdomen, pelvic area or genital area
  • Blood in the semen
  • Blood in the urine
  • Low semen volume
  • Pain when urinating

Keep in mind that these symptoms may also indicate other conditions related to the pelvis, urinary tract or reproductive system. You should consult your doctor if you are experiencing any symptoms that could be due to a problem with the seminal vesicles.

Summary

The seminal vesicles are a pair of small glands that produce and store most of the fluid that makes semen. This fluid is expelled from the seminal vesicle into the ejaculatory duct during ejaculation. It then continues on where it combines with sperm and other fluids that make up the semen.

Conditions affecting the seminal vesicles are very rare and do not commonly occur. If you experience symptoms similar to those described above, make sure to talk to your doctor.

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