There are two testicles in humans. They are contained in an outer skin sac, the scrotum (or bursae), which hangs down between the legs from the base of the penis. The testes are ovoid in shape, measure approximately 4 cm in length and 2,5 cm in diameter, weighing approximately 20 grams.

The testes are covered with an outer membrane, the albuginea. They are divided inside by lobules (more than 200). Each lobule contains U-shaped tubes, the seminiferous tubules. These are the tubes that make the sperm, there are one to four per lobules. The tubes continue in a network of canals, the net witness. The sperm then enter a duct that constitutes the first segment of the genital tract, the epididymis. It then joins the vas deferens. It is a comma-shaped structure that covers the top of the testicle and then descends along the edge.

In the fetus, the testes are first located in the abdomen and then descend into the scrotum before or after birth. The testicle is held in the scrotum by a spermatic cord which is made up of blood and lymphatic vessels, nerves, and the vas deferens.

The testis is the male sex gland. It has two functions: the production of sperm and the secretion of sex hormones, especially testosterone.

La spermatogenesis is the process of sperm formation. It begins at puberty and lasts a lifetime. Every day, millions of sperm are produced from so-called germ cells.

In the seminiferous tubules, stem cells are produced, these are the spermatogonia. Under the action of follicle-stimulating hormone (FSH, for follicle-stimulating hormone), these cells undergo successive divisions to reach the stage of mature sperm. This cycle lasts 74 days in humans. The sperm are then released into the tube and pushed into the epididymis. When stored, they reach full maturity there. They continue on their way into the vas deferens, where secretions from the seminal vesicles and prostate combine to form sperm. During ejaculation, semen is ejected from the body through the urethra.

Testosterone is secreted by Leydig cells which are in the space between the tubes. This hormone is already made in the fetus before its production is interrupted and does not resume until puberty. At this time, the luteinizing hormone (LH, for luteinizing hormone) stimulates the Leydig cells which produce testosterone. This male hormone is synthesized from cholesterol.

La Testosterone helps in the production of sperm. But it is also responsible for stimulating the development of the genitals, the appearance of sexual desire (libido) and secondary sexual characteristics (deep voice, hair on the body and face and larger muscles).

Testosterone is produced continuously throughout life.

Testicular cancer : relatively rare cancer, it affects about 1 in 20 men. It remains, however, the most common form of cancer in adolescents and young men (between puberty and 000 years), the average age of diagnosis being 45 years . It has also been steadily increasing by 37% per year in France, between 2,5 and 1980. Testicular cancer is one of the cancers that is best treated, since the cure rate is approaching 2005% (less than 100% mortality).

Benign tumors : they are either lipomas or fibroids. However, these are rare cases.

Sterility (infertility) : Male infertility is mainly due to a too low production (oligospermia) or a total absence (azoospermia) of sperm in the semen.

Vasectomy : definitive method of male contraception. It is a surgical intervention which consists in ligating the two vas deferens which prevents the sperm from mixing with the constituent fluids of the semen. After the procedure, sperm are still produced in the testes, but they are reabsorbed by the body. As the secretion of testosterone is not modified by the operation, the erection and ejaculation are therefore not altered.

Testicular ectopy (or cryptorchidism): the testis (s) are not naturally descended into the scrotum during fetal life or in the first years of life. Ectopia requires surgery, orchidopexy (see Examinations and explorations).

Pain and swelling of the testicles

Testicular torsion : twisting of the spermatic cord which contains blood vessels. The flow of blood to the testicle is then interrupted which can lead to necrosis (death of the testicle) if nothing is done. This torsion is due to an abnormality of fixation of the testicle in the scrotum that appears during pregnancy. It affects children and young adults and is exceptional in men over 30 years old. It manifests itself in sudden and intense pain. Rapid surgery is required to untwist the spermatic cord.

Hydrocele : accumulation of water around the testicle, sometimes causes impressive swelling of the entire scrotum. Usually, hydrocele is painless and requires surgery to restore the testicle to its normal size.

Varicocèle : varicose veins (varicose veins) of the spermatic cord veins. The blood circuit is blocked and blood circulation is slowed down. Result: sperm production is reduced.

Orchiépididymite : inflammation of an epididymis (or epididymitis) and inflammation of a testicle, most often accompanied by fever and burning when urinating.

Testicular trauma : it can appear following a blow to the testicles: it can be a scrotal hematoma, a contusion or even a “fracture” of the testicle.

Genital infantilism : testosterone deficiency. At puberty, secondary sexual characteristics do not appear in adolescents, their genitals remain those of a child.

Orchite ourlienne : testicular inflammation following mumps disease. The inflammation affects only one testicle in the majority of cases (70 to 85%). Orchitis results in a flare-up of fever, swelling, pain and warmth in the testis and scrotum which is usually accompanied by abdominal pain and vomiting. It generally affects young men who are pubescent (20 to 30% of cases).

Certain factors can alter spermatogenesis. Several studies suggest that taking antibiotics has adverse effects on spermatogenesis or sperm function. Tetracycline6,7 for example, used in particular in the treatment of acne or STIs, would decrease sperm motility. It is also possible that penicillin inhibits their formation (8).

Tobacco (9) and alcohol consumed in excess can cause the formation of abnormal sperm which affects the quality of sperm and can lead to infertility.

Some pesticides would have harmful effects on the quality of semen. A study (10) for example showed a decrease in sperm count of 49% in men who consumed fruits and vegetables with the highest levels of pesticide residues compared to men who consumed fruits with pesticide concentrations. lower. Their sperm count was then 86 million per ejaculate against 171 million in normal times.

Self-examination of the testicles: regular observation of the shape and appearance of the testicles. Technique effective in the early detection of cancer because it allows the detection of changes (lump or lump, pain, feeling of heaviness) (11). It is advisable to practice it once a month from the age of 15. It is necessary to inform your doctor of any abnormality.

Imaging:

Ultrasound: imaging technique that relies on the use of ultrasound to visualize the internal structure of an organ. In the event of a cancer diagnosis, this examination is performed systematically and allows the affected testicle to be explored. The second testicle is also examined to verify that no suspicious mass is present.

Scanner: diagnostic imaging technique which consists of “scanning” a given region of the body in order to create cross-sectional images, thanks to the use of an X-ray beam. The term “scanner” is actually the name of the medical device, but it is commonly used to name the exam. We also speak of computed tomography or computed tomography. In cancer, a thoraco-abdominal-pelvic scan determines whether there are metastases to organs other than the testis.

MRI (magnetic resonance imaging): medical examination for diagnostic purposes carried out using a large cylindrical device in which a magnetic field and radio waves are produced to generate very precise images, in 2D or 3D, of the testis. MRI is a very powerful examination for studying tumors (shape and appearance).

Testicular biopsy: an examination that involves taking a sample of tissue from one or both testicles and examining it. The biopsy is mainly done to determine the cause of a man’s infertility or to determine whether a tumor is cancerous.

Blood test for markers: There are three markers of testicular cancer: AFP, total hCG and LDH. They are present in the blood and their concentration gives indications on the progression of the disease11.

Orchidectomy: Surgery that removes a testicle. This operation is systemic in cancer to remove the tumor. It does not cause infertility since the second testicle remains.

Orchidopexy: surgical intervention that fixes the testicle (s) in the scrotum when they are not naturally descended.

394: the number of words designating the testicles in the French language (waltzes, orphans, purses, balls, etc.). In many civilizations, they are the symbol of courage and virility (14).

At certain times, from Egypt to imperial China via the kingdom of Byzantium, men were castrated by removing their two testicles: the eunuchs. Etymologically, the word comes from ancient Greek and means “bed keeper”. The eunuchs were originally tasked with guarding the harem. In some civilizations, such as Chinese civilization, being a eunuch was an essential prerequisite for entering the high ranks of diplomacy. In the case of China, removing the testicles ensured that no member of the imperial service could found a dynasty.