Male Reproductive System
The male reproductive system is located in the pelvic region of the body and consists of a pair of testes , Accessory reproductive ducts , accessory reproductive glands and penis.
Testes
Testes are male gonads and developed in the abdominal cavity.
At the last two months before birth, Testes descend through the inguinal canal into a pouch-like structure called scrotum.
They are located outside the abdominal cavity or located in scrotum because testes require lower temperature than body temperature ( less than 2 to 2.5 degree Celsius) for formation of sperm through spermatogenesis.
Structure of testes -
Each testis is an oval in shape and covered by the layer of white fibrous connective tissue called tunica albuginea. Testes are composed of about 250 compartments called testicular lobules. Each lobule contains seminiferous tubules which are functional units of testes. Seminiferous tubules open into the rete testis.
Interstitial cells or Leydig cell, which produce male sex hormones testosterone or Androgen . These cells are located between the seminiferous tubule.
In addition to this, another type of cells that are located at the periphery of the seminiferous tubule are called sustentacular cells of Sertoli's cells. These cells provide nourishment for spermatogenesis.
Primary germ cells that are developed during the embryonic development, are responsible for formation of spermatogonia in the testicular lobule at the layer of seminiferous tubule.
These spermatogonia lead the formation of sperm through spermatogenesis.
Accessory male reproductive Duct
Sperms are passed through various ducts to release the outside of the body. These various ducts are named accessory reproductive ducts. These are - Epididymis, vas deferens, ejaculatory duct, and urethra.
Epididymis
Sperms are released from the testes through rete testes and enter into the epididymis. Each epididymis is a long and coiled tube When the sperm make entry into epididymis they are immature and not able to fertilize the ova.
The function of epididymis is maturation and storage of sperm. Mature sperm are stored in the lower portion of the epididymis.
Vas Deferens or Ductus Deferens
The vas deferens is a muscular tube that runs from the epididymis.
It begins from the epididymis and turns over the posterior margin of the testes In form of a ring .The vas deferens make entry through the inguinal canal and pass along the pelvic wall.
It crosses the ureter and posterior portion of the urinary bladder, and then descends toward the prostate gland.
Each Vas deferens enlarges to form an ampulla. Sperms are also stored in vas deferens, near the epididymis.
The peristaltic movements push the sperm through the tube to move outside from gas deferens.
The vas deferens is also a component of the spermatic cord. These spermatic cords which have vascular and neural structures provide the supply of blood the testes.
The spermatic cord contains the vas deferens, testicular artery and veins, lymph vessels, testicular nerve, cremaster muscle.
The cremaster muscles elevates the testes at the times of sexual stimulation.
Ejaculatory Duct
Ampulla part of each vas deferens joins the seminal vesicle to form an ejaculatory duct. Each ejaculatory duct passes through the prostate gland and open into the urethra.
Urethra
The urethra extends from the urinary bladder and opens externally at the tip of the penis. It is a common passage through which sperm and urine release from the urinary system. The male urethra is divided into three regions - Prostatic urethra, Membranous urethra and penile urethra. The ducts of bulbourethral glands open into the penile urethra.
Accessory male reproductive Glands
The accessory glands of the male reproductive system are the seminal vesicles, prostate gland, and the bulbourethal These glands secrete fluids and make semen along with the sperm. Secretion of these glands is called seminal plasma that is rich in fructose, calcium and some enzymes.
Seminal Vesicles
The Seminal vesicles are paired and join with the vas deferens to form an ejaculatory duct that opens into the urethra.
The fluid from the seminal vesicles is rich in fructose, which provides an energy source for the mobility and viability of the sperm.
Prostate gland
The prostate gland is single and located just inferior to the urinary bladder and encircles the urethra. It is also called walnut gland. The secretions of the prostate are milky and alkaline. The secretion of prostate glands is to provide the motility of the sperm.
Bulbourethral Glands
The bulbourethral gland or Cowper's glands are paired and located near the base of the penis. During the sexual stimulation, the bulbourethral glands secrete an alkaline fluid. This fluid neutralizes the acidity of the urine and provides lubrication for the penis during intercourse.
Penis
The penis is a copulatory organ, located near the scrotum.Penis plays a role for insemination or it transfers sperm to the vagina. The penis consists of three columns of tissue. Out of these, The two dorsal columns are the corpora cavernosa And the single is ventral column is corpus spongiosum.
Seminal Fluid or Semen
Seminal fluid or semen is alkaline in nature and is mixture of sperm and secretions from the accessory glands. Secretions from the seminal vesicles make about more than half of the volume of the semen and remain is from the prostate gland. The secretions from the bulbourethral gland contribute only a small volume of semen.
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