The testes are the male reproductive glands. Each oval-shaped testicle is approximately 4-5 cm long, 3 cm deep and 2.5 cm wide. In-utero they develop in the abdomen beneath the kidneys, but before birth will gradually descend through the abdomen and the inguinal canal to enter the scrotum.
As the testes descend, they bring with them a layer of peritoneum from the abdomen. This connection between the abdomen and the scrotum gradually becomes obliterated, leaving a separate sac surrounding each testis. This sac forms the outer layer of the testicular capsule; and is called the tunica vaginalis. The inner layer of the testicular capsule is a tough, blue-white fibrous capsule called the tunica albuginea, which projects into the testis as septa, dividing the testis into cone-shaped lobules.
The testicles also bring with them layers of the abdominal muscles and fascia that form the spermatic cord, suspending the testis from the abdomen.
The testes function to manufacture sperm cells and hormones. Each testis is divided into 200-300 lobules by septi originating from the tunica albuginea. Within each lobule are 4-coiled seminiferous tubules, the lining of which 'secretes' sperm cells. The tubules then converge to form the rete testes which is connected to the epididymis via efferent ductules. Sperm travel through these ducts to be stored in the epididymis until ejaculation.
The spermatic ducts function to carry sperm from the testis to the urethra. They can be described in 3 parts;
The seminal vesicles are paired thin-walled tubes approximately 10-15 cm long that are coiled into sacs approximately 5 cm in length. They lie on the back of the bladder, lateral to the ductus deferens. Inferiorly they join with the ductus deferens to form the ejaculatory ducts, which run through the prostate gland to empty into the prostatic urethra.
They produce a yellowy seminal fluid containing prostaglandins and proteins, which forms 60% of the volume of semen. It is seminal fluid that causes the semen to coagulate after ejaculation.
The penis is the male organ of copulation and is the common outlet for both urine and semen. It contains many venous sinuses which can become engorged in blood, causing erection.
The penis is made of three tubes held together by fascia;
Paired tubes that run along the top of the corpora spongiosum. They attach to the ischial rami of the hip bone and the glans penis.
The prostate is the largest of the accessory glands of the male reproductive system, measuring about 3 cm in diameter. It lies underneath the bladder and surrounds the beginning of the urethra. The posterior surface of the prostate can be easily palpated through the anterior wall of the rectum.
The prostatic urethra and the ejaculatory ducts travel through the gland and open into the prostatic urethra.
It is composed of many follicles that drain into 15-25 excretory ducts that open into the prostatic urethra. They produce a thin, milky fluid that comprises approximately 30% of the volume of semen and provides nourishment for the sperm.
The bulbo-urethral glands are paired, yellow glands approximately 1cm in diameter. They are found behind and to the sides of the membranous urethra and above the bulb of the penis. They are surrounded by the sphincter urethrae.The ducts of the bulbo-urethral glands are approximately 3 cm and open into the spongy urethra in the bulb of the penis.
They produce a clear fluid prior to ejaculation which serves to neutralize the acidic environment of the urethra and the vagina. It also adds some lubrication for the penis during sexual intercourse.