Anatomy & Physiology of the Male Reproductive System

Male reproductive organs

Male reproductive organs are the following:

1. Scrotum:It is the hanging skin sac in between the thighs. It is formed of pigmented skin and has two compartments, in which are suspended two testes.

2. Testes:A pair of sex glands – two testes are suspended in the scrotum by spermatic cord. Each testes is whitish, ovoid solid gland. They are the male gonads and produce

spermatozoa and testosterone. The testosterone hormone is responsible for the secondary sexual characteristics of male. It is also responsible for production of sperms, along with the follicle-stimulating hormone.

There are three layers in the testes.

· Tunica vasculosa is an inner layer of connective tissue.

· Tunica albuginea is the fibrous covering, which divides the testes in to 200-300 lobules.

· Tunica vaginalis is the outer covering, which is made up of peritoneum.

3. Seminiferous tubules: These are the place where spermatogenesis or the production of sperm takes place. These tubules join to form a system of channels, which lead to the epididymis.

4. Epididymis: It is a coiled tube traveling down to the lower pole of the testes where it leads into the vas deferens. The spermatic cord transmits the deferent duct up into the body. The function of the deferent duct or vas deferens is to carry the sperm to the ejaculatory duct.

5. The seminal vesicles are two pouches situated posterior to the bladder. They produce a viscous secretion to keep the sperm alive and motile.

6. Ejaculatory ducts are small muscular ducts to carry the spermatozoa and the seminal fluids to the urethra.

7. Prostate gland produces a thin lubricating fluid, which enters the urethra through ducts. Prostate glands surround the urethra at the base of the bladder lying between the rectum and the symphysis pubis.

8. The penis: The root lies in the perineum, from where it passes forward below the symphysis pubis. It carries the urethra for the passage of both urine and semen.

The male hormones:

Under the influence of the gonadotrophic releasing hormone from the hypothalamus, the anterior pituitary gland produces follicle stimulating hormone (FSH) and luteinising hormone (LH). FSH acts on the seminiferous tubules to bring about the production of sperm. LH acts on the interstitial cells, which produce testosterone. Testosterone is responsible for the secondary sex characteristics such as deepening of the voice, growth of the genitalia and growth of the hair on the chest, pubis, axilla and face.

Formation of Spermatozoa

Production of sperm begins at puberty and continues throughout adult life. Spermatogenesis takes place in the seminiferous tubules under the influence of FSH and testosterone. The matured sperms are stored in the epididymis and the vas deferens until ejaculation. At each ejaculation, 2-4 ml of semen is deposited in the vagina. The seminal fluid contains about 100 million sperms per ml, which move at a speed of 2-3mm per minute. The individual sperm has a head, a body and a long mobile tail. The sperm has an acrosome, which contains enzymes to dissolve the covering of the ovum in order to penetrate it.