Synonyms
prostate gland, prostate cancer, prostate enlargement
Function of the prostate
The prostate gland is a gland that produces a secretion that is released into the urethra during ejaculation (ejaculation) and thus to the outside. The prostate secretion makes up about 30% of the seminal fluid. The pH value of the secretion is about 6.4 and is therefore somewhat more basic than the acidic level in the vagina.
The prostate secretion thus increases the probability of sperm surviving in the acidic vaginal environment. The prostate secretion also contains other substances that have an effect on the motility of the sperm and make the ejaculate generally thinner. The latter substance, which affects the thin fluid of the ejaculate, is the so-called prostate-specific antigen (PSA), which can also be detected in the blood for diagnostic purposes.
Where do you look for this organ, which resembles a halved apple and causes so many men concern? In order to explain its anatomical position in men in an understandable way, an introduction to the structure of the pelvis is necessary. The pelvis (pelvis) resembles a funnel that leans forward.
Towards the top (cranially) it passes into the abdominal cavity without separation. The lower (caudal) narrow opening of the pelvis (the funnel) is closed by muscles and connective tissue, the unit of which is called the “pelvic floor“. This is the area where an expert expects the prostate gland.
The prostate gland is located exactly between him and the urinary bladder (vesica urinaria), whereby its chestnut-like shape wraps around the male urethra like a ring. This can be imagined as if a clenched fist (prostate gland) is clasping a straw (urethra). Directly above the prostate, the bladder finds its place under the bowels of the pelvis.
Because of this, the prostate supports the neck of the bladder and thus the natural closure of the bladder. Next to (laterally) as well as under (caudally) the prostate lies the pelvic floor, which it partially penetrates with its tip, while its base, as mentioned above, lies above the bladder. Furthermore, the prostate gland is accessible via the perineum, both surgically and for massage.
In addition, it is of utmost importance to know what lies in front and behind the prostate. In front of it is the “Ligamentum puboprostaticum”, a small ligament that hangs from the pubic bone (Os pubis, part of the hip bone). Behind it, however, is the far more important positional relationship to the end of the gastrointestinal tract, the rectum.
Only a thin connective tissue skin (Fascia rectoprostatica) stands between them. This makes it possible to palpate (palpate) the prostate from the rectum, to visualize it with ultrasound (Transrectal Ultrasound, TRUS) and to operate. Changes in its usually coarse, bulging elastic composition with a smooth and even surface usually do not escape the fingers of an experienced doctor.
This procedure is called “digital rectal examination” (DRU). Equipped with the knowledge of the location of this gland, we approach its function. How does the secretion of the prostate get to its place of action and what do we need it for anyway?
In order to answer this question, we first need to clarify the production and drainage system of the male semen. The freshly obtained ejaculate is called “sperm” and consists of cells, the “sperm” (synonymous with spermatozoa, singular spermatozoon), and the seminal fluid. While the cellular components come from the testicles (testis), the liquid is mainly obtained from the accessory gonads, which also include the prostate.
The spermatozoa (sperm) are known from everyday representations: usually milky white with a small head and long, movable tail (flagellum), the spermatozoa flit through the most diverse scenarios. In the head they carry the male genetic material in the form of 13 chromosomes (half (haploid) chromosome set), in order to fuse with a female egg cell (ovum) to new life in the theoretical ideal case. Under conceivably complicated regulation, spermatozoa are created in the testes and enter the sperm duct (ductus deferens) via the ducts of the epididymis.
Together with numerous other structures, this forms the spermatic cord (funiculus spermaticus), which finally passes through the known inguinal canal (Canalis inguinalis) on our abdominal wall. Later, the spermatic duct within the prostate meets the central duct of the vesicle gland (Ductus excretorius). After unification, the new vessel is simply called the “injection canal” (Ductus ejaculatorius), which opens into the part of the urethra that is surrounded by the prostate (Pars prostatica urethrae).There, the spray channel ends on a small elevation, the seminal hill (Colliculus Seminalis).
Directly to the side of the seminal mound, the numerous ducts of the prostate gland, which drain the prostate secretion, lead into the urethra. The urethra now penetrates the second layer of the pelvic floor (diaphragm urogenitale) and runs inside the penis up to its opening at the glans penis. If the prostate is viewed from the outside, it is often divided into lobules.
The right and left lobes (Lobus dexter et sinister) are connected by a central lobe (Isthmus prostatae, Lobus medius). In medicine, every complete description of an organ includes a reference to the organization of the blood and lymph vessels and the nerve tracts. Blood supply and lymph drainage of the prostate gland result from its connection to vessels of the bladder and rectum.
The nerves that reach the prostate gland originate mainly from the so-called “autonomic nervous system“. They control their activity and the shortening (contraction) of the local muscles (see below), but are not capable of directing pain into the man’s consciousness. Here, an incision has been made parallel to the forehead (frontal incision): the prostate gland surrounds the urethra.
Within the urethra, a mound bulges into its interior, the seminal mound. On this mound, a small channel with the preliminary sperm ends from each half of the body. Directly next to the seminal mound, the numerous excretory ducts of the prostate gland lead into the urethra!
- Bladder
- Urethra
- Prostate
- Seed mound with the two openings of the spray channels
- Prostate excretory ducts
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