Seminal vesicle

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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The seminal vesicle (vesicula seminalis) is a pair of glands that attach to the prostate. It contributes a secretion to the ejaculate that nourishes the sperm and enables it to move. The excretory duct of the seminal vesicle flows into the urethra as the ductus excretorius together with the spermatic duct (ductus deferens). Read everything you need to know about the seminal vesicle!

What is the seminal vesicle?

The seminal vesicle (vesicula seminalis) is a paired gland next to the prostate. It produces an alkaline and high fructose secretion that is added to the ejaculate. The proportion that this secretion contributes to the ejaculate varies between 60 and 70 percent.

How does the secretion get into the ejaculate?

From each of the two epididymis a spermatic duct (ductus deferens) comes from the scrotum and passes through the inguinal canal into the small pelvis. The right and left vas deferens unite with the excretory ducts (singular: ductus excretorius) of the two seminal vesicles, pass through the prostate and then open into the urethra just below the urinary bladder. In the further course one speaks of the urinary tube.

The sperm that come from the testes or epididymis are mixed with their secretion when the excretory ducts of the seminal vesicles converge. The prostate also contributes a secretion. The entire ejaculate is then transported to the outside via the urinary tube during the ejaculation.

What is the function of the seminal vesicle?

The paired seminal vesicle contributes a secretion to the ejaculate, which supplies the sperm, which come from the testicles and epididymis, with fructose (fruit sugar). The sperm use the fructose as a source of energy in order to be able to move.

The pH value of the secretion of the seminal vesicles is in the alkaline range and thus also promotes the mobility of the sperm, which until then were kept immobile in an acidic environment.

The secretion of the seminal vesicle also contains other substances: Proteins such as semenogelin form a gel coat around the sperm in order to prevent their premature maturation (capacitation), which should only take place through the secretion of the uterus (cervical secretion) in the vagina.

The secretion also contains prostaglandins - tissue hormones that stimulate the contractions of the muscles of the female genital tract.

Where is the seminal vesicle located?

The seminal vesicles are located between the back of the urinary bladder and the wall of the rectum above the prostate. Its surface has a hunched structure, and inside there are many folds of the mucous membrane of various sizes that form chambers. Occasionally it may contain seed threads, but in principle the paired seminal vesicle is not a reservoir for seed threads, but a gland.

What problems can the seminal vesicle cause?

If the prostate is inflamed (prostatitis), the pair of seminal vesicles can also be inflamed. Isolated inflammation of the seminal vesicle is rare.

Seminal vesicle tumors (leiomyomas, carcinomas and sarcomas) are very rare. More common is a tumorous infiltration (i.e. immigration of cancer cells), which starts from a prostate carcinoma (prostate cancer).

A seminal vesicle fistula can result from injury or from inflammation. The tubular fistula then connects the seminal vesicle to the urinary bladder or rectum.

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