- Hormonal control of testicular function
- Testes and Epididymes
- How sperms transfer towards the urethra
- Seminal Vesicles
- The Prostate
Τhe male reproductive organs are: testes, epididymes, ejaculatory ducts (ducti deferens), ptostate and seminal vesicles.
Hormonal Control of Testicular Function
The role of testes is highly important and has to do with the production of sperms and testosterone hormone. Testicular function is regulated by 2 hormones produced in the pituitary gland of the brain: FSH (Follicle-Stimulating Hormone) -for regulating spermatogenesis- and LH (Luteinizing Hormone) -for regulating testicular testosterone production. The pituitary function is controlled by the hypothalamus, located next to the pituitary gland, and produces GnRH (Gonadotropin-Releasing Hormone), regulating the pituitary hormonal secretion. In other words, there is a hypothalamic-pituitary-testicular hormonal axis, which is interregulated: high testosterone levels have an inhibitory effect on the hypothalamus and fn the pituitary FSH and LH secretion , whereas low testosterone levels increase the pituitary hormonal secretion and activate testes. In other words, the hypothalamic-pituitary-testicular axis regulates testicular function.
Testes and Epididymes
Testes are the primary male genital glands located in the scrotum, a sac (pouch) of skin with many internal membranes. Their anatomical location outside the body allows them to retain lower temperature than the respective body temperature; this is very important for spermatogenesis and fertility.
Testes are oval-shaped organs with dimensions of 4x2,5x2,5 cm. They are surrounded by the tunica albuginea, which is the inner testicular mebrane forming 200-300 lobules that contain the seminal ducts producing sperms. The process of creation and maturation of sperms is called 'spermatogenesis' and lasts about 70±4 days. Under the effect of testosterone produced in testes by specific cells -the Leydig cells-, sperms are released from the lumen of seminal ducts ending up in the epididymis. The epididymis is a single convoluted duct, 5-7m in length, contributing to the nutrition, ultimate maturation and mobility of sperms. The epididymes are vulnerable to inflammations causing pain and swelling. It is highly essential that inflammation are treated on time.
How sperms transfer towards the urethra
Ductus deferens (vas deferens) is a thin muscular tube, 45cm in length, starting at the tail (lower end) of the epididymis, helping the upward movement of sperms. The seminal duct initially courses towards the bladder and forms the seminal ampulla (at the height level of the prostate). It then unites with the duct of a seminal vesicle and the fusion of these two ducts form the ejaculatory duct,; this duct passes through the prostate and terminates in the prostatic segment of the urethra and, more specifically, at the seminal colliculus. On their way, sperms get mixed with the seminal fluid produced by the accessory genital glands. Accessory genital glands are: the seminal vesicles, prostate, bulbourethral and urethral glands.
Seminal vesicles are small sacs (pouches), 5cm in length, producing a sticky fluid that is the 60-70% of the seminal fluid content. The rest 30-40% comes from the prostate.
The prostate is a chestnut-shaped gland, 3-4cm in dimensions, composed of fibrous muscular tissue and glands. It is exactly here where the sticky fluid of seminal vesicles turns into a thin watery fluid, with the contribution of prostate enzymes and mainly PSA (Prostate-Specific Antigen). Also, here testosterone is converted into an even more potent androgen, DHT (Dihydrotestosterone). The prostate is highly susceptible to infections, the so-called 'prostatitis'. Acute prostatitis has intense symptoms, such as high fever, urinary frequency and painful urination. It is treated with antibiotics, while more severe cases may require hospitalization. Chronic prostatitis is accompanied with mild symptoms, such as pain in the perineum -below the testes- or even in the testes themselves, urinary symptoms and frequent erectile problems. Very often it is very hard to treat, particularly when no microbe is found in the semen, so in this case we are talking about a chronic pelvic pain syndrome.
Lastly, bulbourethral or Cowper's glands, are small glands -about the size of a lentil- which produce a clear, viscous, alkaline secretion that is discharged through the 3-4cm long urethra.