The mature male sex organs that develop normally are divided into internal and external parts: the external genitalia and the internal genitalia. The internal reproductive organs are composed of testis, epididymis, vas deferens, ejaculatory ducts, urethra, seminal vesicles, prostate, bulbous urethral glands and so on.
Testis: Testis is the male gonads, oval glands, left and right one, surface light Slippery, respectively suspended by the spermatic cord in the scrotum. Each testicle weighs 10 to 15 grams and averages 3.34 cm in length, 2.32 cm in width and 1.74 cm in thickness. It’s a little bigger on the right. If testicular volume is too small, it will cause poor spermatogenesis and affect fertility. There are more than 200 lobules in testis, each lobule has 2 ~ 4 curved spermatogonial tubules, and the spermatogonial cells in the tube wall can develop into spermatozoa. Between the convoluted tubules are mesenchymal cells, which secrete androgens. The functions of the testes include producing sperm and secreting androgens.
Epididymis: The epididymis is close to the upper and posterior edge of the testicle. It is a half-moon shaped body with one on the left and right sides. It is divided into three parts: head, body and tail. The epididymal head was enlarged and the body and tail gradually tapered. The primary function of the epididymis is to store sperm. The maturation process of sperm takes place in the epididymal environment, and sperm usually stay in the epididymis for 10 to 25 days to gain the ability to motility and fertilization. The tail of the epididymis is where sperm are stored. During sperm discharge, due to the contraction of epididymis and vas deferens, sperm and semen are discharged through the ejaculatory duct and urethra.
Vas deferens: The vas deferens is a pair of smooth muscle tubes, white, about 40 cm long, about 3 mm wide, divided into testicular segment, spermatic cord segment and pelvic segment.
Ductus ejaculatorius: The vas deferens rises along the posterior edge of the testis and enters the pelvic cavity to meet the excretory duct of the seminal vesicles, forming the ductus ejaculatorius. The ejaculatory duct is about 2 cm long, surrounded by the prostate, and opens in the verumonium of the posterior wall of the urethra prostatic part. The ejaculatory duct only opens when the sexual excitement reaches a certain threshold, so that the semen is ejaculated.
Urethra: The male urethra has both the function of excreting urine and sperm. 12 ~ 20 cm long. Some of them, the bulbous urethral gland, secrete liquid, participate in the composition of semen, and have the role of lubricating the penile head during sexual intercourse.
Vesicles: A blind sac emanating from the end of the vas deferens, a pair of shuttles attached to the base of the bladder. One end of the tube is closed, the other end is open, and the vas deferens combined to form the ejaculatory duct. Its function is to secrete seminal vesicle fluid and participate in the synthesis of semen.
Prostate: Located in the pelvic cavity at the base of the bladder, near the bladder neck, around the urethra, in the shape of a flat chestnut. The prostate is about 4 centimeters wide, 3 centimeters long, 2 centimeters thick and weighs about 20 grams. The prostate gland is the largest male accessory gonad and its main function is to secrete prostatic fluid. Prostatic fluid contains a lot of sodium, potassium, zinc and other elements, has an important effect on the physiological function of sperm. This fluid is constantly produced and secreted by glandular cells, and can be produced in large quantities during sexual arousal. Some of it seeps into the urethra to lubricate the urethra.
Bulbous urethral gland: below the prostate, on both sides of the urethra, for a pair of pea size round bodies. Before sexual arousal and ejaculation, a small amount of secretions enter the urethra. The secretions are alkaline and can neutralize acidic urine, which is conducive to sperm survival. The secretions of the bulbous urethral glands have lubricating effects.