The Man

The male reproductive system is a series of organs with vital roles during sexual intercourse and procreation. The purpose of the organs in the male reproductive system is to perform the following functions:

  • To produce and secret male hormones.
  • To produce, sustain and transport sperm (the male reproductive cell) and other components of protective fluid (semen).To release sperm inside the female reproductive system during intercourse.

Several organs make up male reproductive system, they can be found inside and outside of the body.

The external organs are penis, scrotum and testicles.

Penis- the male organ used in sexual intercourse. It is cylindrical in shape and contains the urethra and the external opening of the urethra. There are large chambers of sponge-like erectile tissue in the penis which allows it to fill with blood when the man is sexually aroused. As the penis fills with blood, it becomes rigid and erect causing it to increase in size which allows penetration during intercourse. The main function of the penis is to deliver semen into the vagina during intercourse.

Scrotum- is the loose pouch-like sac that hangs below the penis and encases the testes. The scrotumconsists of 2 side-by-side pouches which contain testis located in each pouch. When the testes become too warm to support normal sperm development, the scrotum relaxes to move the testes away from the body’s heat. On the contrary, the scrotum contracts to move the testes closer to the body’s core heat when temperatures drop below the ideal range for sperm development.

Testes- also known as the testicles. They are responsible for producing sperm and testosterone (primary male hormone). Normally men have two testes.

Epididymis- is a long thin coiled tube resting at the back of each testicle. Sperm produced in the testes moves into the epididymis to mature, since the sperm that emerge in the testes are immature and incapable in fertilization.

The internal organs of the male reproductive organs are the following:

Vas Deferens-transports the mature sperm to the urethra in preparation for ejaculation of semen into the female reproductive system. It is also called ductus deferens.

Spermatic cords-they contain the ductus deferens along with the arteries, veins, lymphatic, nerves and the excretory ducts of the testes.

Seminal Vesicles- are sac-like pouches that are attached to the vas deferens near the base of the bladder. They produce liquid which contains sugar-rich fluid (fructose) which provides energy for sperm’s survival and helps in their motility.

Urethra- urine exits out of the body through the urethra. In males, it has additional function in the reproductive system that is ejaculating semen when a man reaches the orgasm.

Prostate-is a walnut-sized exocrine gland and produces a large portion of the fluid that helps to nourish the semen. The prostate also contains smooth muscle tissue that can constrict to prevent the flow of the urine or semen.

How does male reproductive system work?

The primary hormones involved in the functioning of male reproductive system are follicle stimulating hormones (FSH) andluteinizing hormones (LH).

FSH and LH are produced by the pituitary gland that is located at the base of the brain. LH in the bloodstream causes cells in the testes to make and release testosterone. During puberty, testosterone is responsible for the development of male characteristics, including muscle mass strength, fat distribution, bone mass, facial hair growth, voice change and libido. FSH is important in sperm production. It supports the function of Sertoli cells, which in turn support many aspects of sperm maturation.

FSH and testosterone work together to stimulate the testes to produce sperm.

How are the sperm produced?

The male reproductive systems comprises of the testes, urethra, vas deferens, prostate gland, seminal vesicle and the penis. Collectively, they produce, store and deliver the Sperm - the male reproductive cell.Sperm production mainly happens in the seminiferous tubules which are a part of the testis.The sperm travels from seminiferous tubules to the epididymis, which is located above the testes. Here the sperm mature, and are stored.

The process of ejaculation begins first when the penis is erect due to increased blood flow there. On sufficient stimulation, the sperm stored in the epididymis will travel through vas deferens, a narrow muscular tube, thatpushes the sperm forward by smooth muscle contractions.

During ejaculation the sperm first arrives in the ampulla, where it mixes with the fluid in the seminal vessels. This Seminal fluid contains fructose sugar which is the energy source for sperm. Also, thefluid is alkaline and help counteract the natural acidic environment of the vagina and uterus. These help give the sperm a better chance of survival.

From the ampulla, this mixture moves through the ejaculatory duct towards the urethravia the prostate gland, where a milky fluid is added to form semen. Finally, the semen is ejaculated from the penis.

Factors affecting sperm production

  • Drugs- some men may have unexpected side effect from the medication that can harm their fertility.
  • Anabolic steroids- these are drugs that are used to build muscles mass and decrease body fat. Anabolic steroids interfere with the hormone signals that are needed to produce sperm. The damage depends on the drug used, dose and how long it has been taken.The use of anabolic steroids by a man can cause infertility because anabolic steroidscontains high levels of testosterone, which gives a negative feedback to the hypothalamus on FSH and LH release and so influence the sperm production.
  • Temperature- testicles hang outside the body because ideal sperm production requires a temperature below the normal core body temperature of 37° C. If exposure to heat is prolonged, it can affect thesperm production process.
  • Smoking- it is well known, that smoking has a negative impact on the number and the motility of sperm. Even after quitting smoking, it takes some time for the semen quality to be restored.
  • Obesity-Fat cells increase the production of the female hormone called “estrogen” and decrease the male hormone called testosterone. Therefore, obesity has a major impact on the sperm production.
  • Parental consanguinity-It has been shown that the sperm quality of man whose parents are first degree cousins is lower than menwhose parents are not related.

Infertility is the conditionin which a couple, who is having regular intercourse and not using any contraception, cannot conceive.

Causes of Male Infertility

Medical causes:

  • Sexually transmitted disease and other infections
  • Ejaculation Problems- Normally during an ejaculation, the muscle at the end of the bladder contracts to prevent sperm from entering the bladder. With retrograde ejaculation this mechanism is not working correctlyand the semen enters the urinary bladder during orgasm instead of going out through the urethra.
  • Varicocele- are enlarged groups of veins in the scrotum. This may prevent normal cooling of the testicles leading to reduced sperm count and reduced motility of the sperm. However, operating on a varicoceleis not indicated, unless the patient has a painful varicocele.
  • Obstruction of the epididymis- it prevents the sperm from entering the vas deferens and getting into ejaculation therefore there will not be any sperm in the specimen. This finding is called azoospermia.
  • Chromosome defects- regarding the number and the shape of the chromosomes. One example is Klinefelter’s syndrome, where a man has an additional X-chromosome. Due to the change in the genetic material, sperm production is reduced or doesnot occur.
  • Chronic illness- e.g. tumor
  • Sexual dysfunction
  • Hormonal problemsMedication side effects
  • Diabetes

Environmental causes:

  • Extreme exposure to pollution and radiation.
  • Overheating of testicles- e.g extreme biking, prolonged sitting, wearing tight clothes

Lifestyle and other causes:

  • Lifestyle- one of the biggest issues that can cause male infertility and low sperm count. Examples arepoor diet,lack of exercise,obesity,stress
  • Excessive alcohol intake- heavy drinking can reduce the quality and quantity of sperm
  • Smoking- men who smoke are more likely to have low sperm counts
  • Stress- affects the couple’s libido

Diagnosing Male Infertility

A full male fertility workup includes recording the family history, physical check-up, performing semen analysis and occasionally other tests (blood test including hormonal values and/ or chromosomal analysis). The semen analysis will analyze the number of available sperm, the shape (morphology) and its motility (ability to move or swim). The information and results will be an important concern in planning the suitable treatment for the couple.

Depending on the result of the initial tests, the doctor may need to perform additional investigations to look for other cause of male infertility. This may include:

  • Genetic Tests- look for any signs of genetic abnormalities
  • Scrotal Exam and Ultrasound- to check the anatomy and exclude tumors
  • Hormone Testing- determines the level of your hormones that are essential in sperm production

Male Infertility Treatment

Over the years, the number of treatment for male infertility has expended. Depending on the cause of infertility, this includes:

  • Lifestyle modification
    • Quit smoking
    • Reducing alcohol intake
    • Moderate exercise
    • Losing weight
    • Dietary control
  • Surgery- e.g. Repair of the blocked vas deferens or varicocele removal
  • Medical Therapy- e.g. treating infections, hormone treatment and medication
  • Assisted Artificial Technology (ART)- e.g.Intra UterineInsemination (IUI), In- Vitro Fertilization (IVF) or Intra-Cytoplasmic-Sperm-Injection (ICSI)

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