1. The Scrotum: It forms a pouch in which the testes are suspended outside the body. It is made of deeply pigmented skin, fibrous and connective tissue and smooth muscle. It is divided into 2 compartments for each testis.
The scrotum keeps the testicles at the right temperature for sperm production, by tightening up and putting the testicles close to the body in cold conditions while it loosen up and the testicles hang down lower in hot conditions. The scrotum lies below the symphysis pubis and between the upper parts of the thigh behind the penis.
2. Testes: These are 2 firmed, smooth and egg shaped organs, each measuring about 2.5cm wide, 4.5cm long and 3cm thick. They are suspended into the scrotum by the spermatic cord.
The testes are the male gonads and produces spermatozoa and testosterone. Testosterone is responsible for secondary sex characteristics. It also joins with FSH to promote production of sperm. The production of sperm is effective at about 30c below the normal body temperature.
It consists of 3 layers:
Tunica Vasculosa – It is the inner layer of connective tissue containing a fine network of capillaries.
Tunica albuginea – It is the fibrous covering beneath the vaginalis, in growth of which divide the testes into 200-300 lobules. Within each lobule are about 1-4 convoluted loops of germinal epithelial cells called semiferous tubes, between the tubes are the interstitial cells that secrets testosterone after puberty.
Tunica Vaginalis – It is the outer layer which is made of peritoneum brought down with the descending testis when it migrated from the lumba region in fetal life. The descent of testis is usually completed by the 8th month of fetal life.
Functions
Sperm production which is later passed to the epididymis where they are stored.
Testosterone production.
3. Spermatic Cord: It suspends the testis into the scrotum. Each cord contains a testicular artery, testicular veins, lymphatics, a deferent ducts and nerves
4. Deferent Duct (Vas deferens): It is about 45cm long. It pass upward from the testis, it merges with the duct from the seminal vesicle and passes through the prostate gland at the ejaculatory duct to join the urethra.
5. Seminal Vesicle: They are 2 pouches situated posterior to the bladders. They’re about 5cm long and pyramid shaped. They produce viscous secretions to keep sperm alive and motile (nourishes). It forms 60% of the semen usually ejaculated.
6. Ejaculatory Ducts: These are 2 small muscular ducts which carry the spermatozoa and the seminal fluid to the urethra.
7. Prostate Gland: It surrounds the urethra at the base of the bladder, lying between the rectum and symphysis pubis. It produces a thin lubricating fluid which enters the urethra through ducts. It is about 4cm long, 3cm wide and 2cm deep. The secretion makes up 30% of semen and is usually milky
8. Semiferous tubules: These are where spermatogenesis takes place. Between the tubules are interstitial cells which secrete testosterone. The tubule joins to form a system of channels which lead to the epididymis.
9. Epididymis: It is a comma-shaped, coiled tube which lies on the superior surface and travels down the posterior aspect to the lower pole of the testis, where it leads into the deferent duct.
10. Bulbo Urethral (Cowper’s) Gland: These are small glands which produces yet another lubricating fluid which passes into urethra just below the prostate gland. The secretion helps to remove traces of urine from the urethra so that the acid in it will not kill the sperm.
11. The Penis: It is the male sex organ. It has a root and a body. The root lies in the perineum, from where it passes forward below the symphysis pubis.The lower 2/3 is outside the body in front of the scrotum. The body surrounds the urethra. It is made of 3 cylindrical masses of erectile tissue and smooth muscles as described below:
Corpus Covernosa: These are 2 lateral column one on either side and in front of the urethra.
Corpus Spongiosum: It is the posterior column which contains the urethra. The tip is expanded to form the glans penis.
The lower 2/3 of the penis is covered in skin. At the end, the skin is folded back on itself above the glans penis to form the prepuce, which is a movable double fold. The penis is extremely vascular and during an erection the blood spaces fill and become distended, due to parasympathetic stimulation which causes arteriolar dilatation and venoconstriction.
2.1.1 PROCESS OF SPERM FORMATION
Spermatogenesis: It takes place in the semiferous tubules under the influence of follicle stimulating hormone (FSH) and testosterone. They become matured as they pass through the long and convulated epididymis, where they are stored. The process of maturation is a lengthy one and takes some weeks. They remain in the epididymis and deferent duct until ejaculation. If this does not occur they degenerate and are reabsorbed. The matured sperm cell has a head, a body and long mobile tail which aids in propelling it forward. The tip of the head is line by an, acrosome which contains enzymes to dissolve the covering of the ovumin order to penetrate it.
At each ejaculation about 2-5mls of semen is released containing about 100million spermatozoa per ml of which about 20-25% are likely to be abnormal.
- 60% is slightly alkaline which help
COMPOSITION OF SEMEN
Spermatozoa – 10%
Seminal fluid – 60%
Prostatic fluid – 30%
Mucus from urethra – negligible.
The composition of the semen is slightly alkaline which helps to neutralize the acidity of the vagina for the sperm to survive.
