Male Reproductive System: how Does it Work?

The male reproductive system is designed to produce, maintain, and transport sperm (the male reproductive cells) and protective fluid (semen) so fertilisation (conception) can occur. The system is also designed to produce and secrete male sex hormones responsible for maintaining the male reproductive system.

Understanding the male reproductive system, what it does, and the problems that can affect it can help you better understand your reproductive health.


The Male Reproductive System

Male Reproductive System



The testes, commonly known as the testicles, are a pair of ovoid glandular organs that are central to the function of the male reproductive system. The testes are responsible for the production of sperm cells and the male sex hormone testosterone. The testes produce as many as 12 trillion sperm in a male’s lifetime, about 400 million of which are released in a single ejaculation.



Is a single, narrow, tightly-coiled tube (in adult humans, six to seven meters in length) connecting the efferent ducts from the rear of each testicle to its vas deferens. It transports and stores sperm cells that are produced in the testes. The epididymis also brings the sperm to maturity, since the sperm that emerge from the testes are immature and incapable of fertilisation.


Vas Deferens

The vas deferens is a tube that connects the testes with the urethra. It is a coiled duct that conveys sperm from the epididymis to the ejaculatory duct and the urethra. Each one is about 30cm and is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. During ejaculation the smooth muscle in the wall of the vas deferens contracts, pushing the mature sperm toward the penis and into the urethra.



The male urethra is a narrow fibromuscular tube that conducts urine and semen from the bladder and ejaculatory ducts, respectively, to the exterior of the body. Although the male urethra is a single structure, it is composed of a heterogeneous series of segments: prostatic, membranous, and spongy. It has the additional function of ejaculating semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.


Accessory Glands

The male accessory glands are: seminal vesicles, prostate gland and bulbourethral glands.

  • Seminal vesicles: these are located within the pelvis and their function is to secrete a significant proportion of the fluid that ultimately becomes semen.
  • Prostate gland: the prostate secretes a slightly alkaline fluid, milky or white in appearance, which normally constitutes around 50-75% of the volume of the semen.
  • Bulbourethral glands: the function of these glands is to produce a clear, salty, viscous secretion (pre-ejaculate) during sexual arousal, to help to lubricate the urethra for spermatozoa to pass through. This fluid neutralises traces of acidic urine in the urethra and helps to remove any residual urine or foreign matter.


What is Sperm?

Sperm are the male reproductive cells. In order to conceive a baby, the genetic material from the sperm must combine with the genetic material from an egg, in a process called fertilisation. Healthy, fully developed sperm are very small (0.05 millimetres long) and cannot be seen by the human eye. These mature sperm are highly specialised cells and are made up of three parts: a head, neck and tail. In the head is a structure called the nucleus, which contains 23 tightly packed chromosomes (genetic material). The head is designed to stick to and then enter (penetrate) the egg. The neck joins the head to the tail. The part of the tail nearest the neck contains the mitochondria, which provides the energy for the sperm to move. The tail moves in a whipping motion to push the sperm towards the egg.


What is Semen?

Semen, also known as seminal fluid, is an organic fluid that may contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs and can fertilise female ova. Semen also contains other components, besides spermatozoa, which nourish the sperm, promote the survival of spermatozoa, and provide a medium through which they can move or “swim”.

Semen is produced and originates from the seminal vesicle. The process that results in the discharge of semen is called ejaculation.


At Rainbow Fertility, our specialists have extensive experience in helping create LGBTQIA+ families. Feel free to contact our friendly team to learn more about the fertility treatment options available to you.

Call: 1300 222 623



Current as at 01.02.2016

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