The prostate is a small, rounded organ that belongs to the male genital system. The latter, in addition to the external genitalia, therefore to the penis and scrotum, also includes the gonads (ie the testicles), the spermatic ducts and some attached glands. The prostate is one of these glands attached to the male genital apparatus. Given the premises, I think it is clear to everyone that the prostate is present only in men.
As can be seen from the image, the prostate is located in the pelvis, therefore in the lower part of the abdomen. Looking at the figure in more detail, we can see how the prostate is placed just below the bladder, in front of the rectum. The gland merges with the two ejaculatory ducts that cross it, and, like a donut, partially surrounds the first part of the urethra, which is therefore called the prostatic urethra. I remind you that the urethra is the small duct that carries urine from the bladder to the outside during urination. In the male, moreover, the urethra serves for the passage of sperm during ejaculation. In an adult man, the prostate weighs about 20 g. Under normal conditions, it generally has dimensions and shape similar to those of a chestnut, with the base facing upwards attached to the lower surface of the bladder, and the apex facing downwards. As we will deepen in the next videos, with over the years, or due to some pathologies, the prostate can enlarge, therefore increase in volume. Precisely because of this position and the relationships described with nearby organs, the enlarged prostate can cause problems with urination, ejaculation or defecation.
To better understand the functions of the prostate, let's now briefly see some of its structural characteristics. The prostate is made up of a fibro-muscular component and a glandular component. The glandular parenchyma consists of a cluster of about 30-50 tubulo-alveolar glands. These glandular formations are entrusted with the exocrine function of the prostate: that is, the processing of prostatic fluid. I remind you briefly that the exocrine glands are glands that pour their secretion outside the body or in any case in cavities communicating with the outside. to the prostate, other examples of exocrine glands are represented by the sweat, salivary and lacrimal glands. Returning to our tubulo-alveolar glands, these open through 15-30 excretory ducts into the prostatic urethra, where they pour their fluid during ejaculation. The glands are also surrounded by a rather thick layer of smooth muscle fibers and connective tissue. During ejaculation, the peristaltic contractions of the muscle fibers compress the glands, which in this way pour their secretions into the prostatic urethra.
As anticipated, the main task of the prostate is to produce part of the seminal fluid. The prostate then produces some of the fluid that carries sperms during ejaculation. In particular, the so-called prostatic secretion contributes 20-30% of the total volume of the ejaculate. This liquid joins the sperm from the testicles and other fluids produced by the seminal vesicles. From this union, the sperm originates, which is expelled in the act of ejaculation. As far as functions are concerned, the prostatic secretion has the task of keeping seminal fluid fluid and of constituting a particularly favorable environment for the survival and motility of spermatozoa. This secretion is also able to exert a bactericidal action and to act on the pH of the vaginal canal, reducing its hostile acidity to spermatozoa. Thanks also to the spermatic fluid after ejaculation, spermatozoa can survive up to 3-5 days in the uterus and fallopian tubes.
By analyzing its composition, it turns out that the prostatic fluid is fluid, milky, slightly alkaline and rich in nutrients, including enzymes, prostaglandins, fructose, citric acid, zinc and other mineral salts. All this, as we have seen, is aimed at increasing the survival and motility of spermatozoa. Among the various components of the prostate fluid, I also remind you of the PSA, acronym of Prostate-Specific Antigen, Italianized in prostate specific antigen. PSA has the important function of thinning the spermatic clot, to facilitate the movement of spermatozoa. In other words, PSA inhibits the coagulation of seminal fluid, so that it can flow easily in the female reproductive environment. As we will see later, the initial screening for the diagnosis of prostate cancer involves the measurement of PSA in the blood. in particular, when the PSA is high it is interpreted as a possible alarm signal that deserves appropriate diagnostic tests.
Before concluding, it is necessary to point out that the prostate is very sensitive to the action of hormones. In particular, its growth and functions depend on male sex hormones, known as androgens. Among the androgens, the role of the protagonists is played by testosterone, produced by the testicles, and by one of its metabolites, dihydrotestosterone or DHA. High levels of dihydrotestosterone are generally associated with an increase in secondary sexual characteristics, such as hair, and predispose to androgenetic baldness and prostatic hypertrophy.
To learn more Prostate: What is it? Functions and Diseases
