Male Reproductive Anatomy: The Complete Guide
Photo by Dainis Graveris on SexualAlpha
Our complete guide to female anatomy.
As you've probably noticed, we love chatting about sex and relationships at Green Condom Club! But first things first: knowledge of your anatomy (and your partner's!) is essential, right?
Sure, most of us know the basics. But who can really tell which organs play a role in making sperm, for example? And so, we thought that it was about time to write a complete guide to male reproductive anatomy.
We'll explore the interconnectedness of all the different parts of the reproductive, urinary, and digestive systems.
What is the reproductive system?
Let's start with the basics. A reproductive system is a group of organs that participate in procreation. While many of these organs are external - the penis, the scrotum, and the testicles - many other essential ones are internal.
The sum of all these organs allows sexual activity, procreation, and urination - the release of liquid waste from the body, constituted of water, salt, and toxins previously filtered by the kidneys.
Additionally, the male reproductive system plays an important role in producing and transporting sperm, seminal fluid, and other secretions produced by sex hormones.
Structure of the male reproductive system
Author: R. Dewaele (Bioscope, Unige), J. Abdulcadir (HUG), C. Brockmann (Bioscope, Unige), O. Fillod, S. Valera-Kummer (DIP), www.unige.ch/ssi. pPublished on the website Sciences, Sexes, Identités of Université of Geneva.
Male reproductive system parts and functions
Let's see how the reproductive system works, starting with the external parts.
The penis
The penis is the male sexual organ: it allows men to urinate, have sex, and reproduce - the latter being permitted by the processes of erection and ejaculation. While the penis is flaccid at rest, it gets harder and bigger during an erection.
A penis is composed of several parts: the base joins the body of the penis to the perineum, located on the abdomen. More precisely, it's a ligament that attaches the penis to the pubic symphysis, that is, the joint between the two pubic bones.
Three different cylinders of erectile tissue run through the middle part of the penis, the shaft (or body). One of them surrounds the urethra: the corpus spongiosum. Constituted by numerous blood vessels, it is said to have the consistency of a sponge because it swells during excitation: the muscles of the penis loosen, thus letting the blood circulate.
Apart from the corpus spongiosum, two paired bodies called the corpora cavernosa allow the penis to swell, lengthen, and harden.
Fun fact? The human penis doesn't have a bone, like most mammals! Instead, an erection (and so, reproduction) depends on blood flow and the hardening of the corpora cavernosa.
The head of the penis is called the glans penis, generally covered by a whitish liquid, the smegma. The skin protecting the upper part of the penis is the foreskin: that's what gets removed during circumcision.
The frenulum of the prepuce is a fold of skin found on the inferior side of the glans. It's a "line" of tissue that retains the foreskin in place, avoiding pulling it back too far away from the tip of the penis. The frenulum also connects the urinary meatus (the urethral orifice) with the penis crown (the corona of glans).
Finally, the urethra canal runs through the penis to allow the passage of urine and sperm (and spermatozoids too): from the bladder to the prostate, before exiting the urinary meatus.
The scrotum and the testicles
A sac of skin protecting the testicles, called the scrotum, lies just under the penis. It allows controlling their temperature, which has to be a few degrees below the temperature of the rest of the body. Why is that? Because temperature directly affects the proper development of sperm and spermatozoids, as they are produced in the testicles.
Both testicles are suspended by a spermatic cord. This cord is made by nerves, blood vessels, the vas deferens, but also the cremaster muscle, which covers the testis. When this muscle contracts (due to cold or excitation), it makes the testis move closer to the body, to regulate their temperature.
The testicles produce testosterone, a sex hormone that supports the development of other sexual traits, such as muscles and hair.
Fun fact: fear not, it's completely normal that testicles aren't identical. They are often at different heights and different in size!
Along with testicles, epididymides are also found inside the scrotum sac. While spermatogenesis - the process of making the spermatozoids - occurs in the testicles, spermatozoids are stoked in the epididymides until maturity. When the walls of the epididymis contract, the spermatozoids are pushed out towards the vas deferens.
The vas deferens allows the spermatozoids to travel from organ to organ to refine their maturation, but also serves as storage until their evacuation during ejaculation. This canal starts from the epididymis, heads out of the scrotum towards the abdomen, before joining the seminal vesicle. The union of the vas deferens with the duct of the seminal vesicle form the ejaculatory duct.
Internal parts of the male reproductive system
The ejaculatory duct is a tube that allows the transport of the spermatozoids, from the seminal vesicle towards the prostate, and then, the urethra.
Under the bladder, the prostate surrounds the urethra tube. It's one of the organs responsible for the production of some of the secretions contained in sperm, such as the prostatic liquid, which feeds and protects the spermatozoids. It also allows the fabrication of a protein that liquefies sperm, thus improving the general mobility of the spermatozoids.
Hence, the prostate plays a direct role in fertility, as the contraction of this organ allows ejaculation. It also stocks up the urine coming right from the bladder, before being evacuated by the urethra.
As for the seminal vesicles, they consist of two pockets behind the bladder. Along with the prostate, they produce the secretions (high in nutrients!) contained in sperm to reinforce the spermatozoids.
The Cowper's glands are two glands located internally at the base of the penis. They are involved in the creation of sperm and seminal fluid. In fact, the seminal fluid is a mix of spermatozoids, liquids from the prostate, the seminal vesicles, and the Cowper's glands. Hence, together, these liquids form sperm, which is evacuated during ejaculation.
Fun fact: when a man has an erection, it automatically blocks the flow of urine. And vice versa: while urinating, the flow of sperm is prevented. In brief, the flow of one stops the other, thanks to the contraction of sphincter muscles.
The male and female urinary systems are almost identical: the bladder (which can stock from 400 to 700 milliliters of liquid!) collects the urine produced by the kidneys, before evacuating it through the urethra.
The last part of the digestive system is the rectum, which marks the end of the colon and leads to the anus. In the shape of a curve, it measures no less than 15 cm. The rectum comprises two parts: the rectal ampulla, which stocks the fecal matter before exiting the anus, and the anal canal, which allows continence.
The anus is the very end of the digestive tract! This orifice is located just after the rectum and regulates defecation, thanks to the sphincters, which play an essential role in controlling continence.
How does the reproductive system function?
Humans' sexual anatomy begins developing as early as puberty, thus providing the ability to procreate. At that time, boys start to produce gametes and spermatozoids, their voice changes, hair becomes abundant, genitals and muscles grow.
The origins of sexes
The development of our genitals occurs while we are still embryos. Thus, sex is genetically and chromosomally determined as early as fecundation, when an egg meets a spermatozoid.
Spermatozoids and ejaculation
While the volume of ejaculation is around 2 to 6 milliliters, a single milliliter contains at least 100 million spermatozoids! Thus, men can produce spermatozoids until death. In comparison, women are born with their stock of oocytes. Period.
From the moment of their creation in the seminiferous tubules of the testicles, it takes around 72 days for spermatozoids to reach maturity in the epididymides.
During ejaculation, these spermatozoids are ejected from the testicles, go through the vas deferens before joining the seminal fluid (created by the seminal vesicle and the prostate), passing through the urethra and exiting the urinary meatus. However, they can't survive longer than a few hours in an acidic environment such as the vagina.
What about hormones?
The proper development of the reproductive system depends on our precious hormones. They are chemical substances present in blood that stimulate and regulate the activity of our organs' cells.
The main male hormones include the following:
The follicle-stimulating hormone allows the functioning of the testicles, sperm production, and spermatogenesis.
The luteinizing hormone controls the sexual glands, the testicles, produces testosterone, and completes spermatogenesis. It contributes to developing secondary sexual traits, such as muscles, libido, etc.
These hormones are created by the pituitary gland (located in the brain), responsible for the secretion of numerous other hormones in our body.
Testosterone is certainly the most famous hormone, often associated with virility. The testicles and the adrenal glands produce it when the boy is still a fetus, then stops at birth, before starting again when entering puberty. Testosterone is responsible for male attributes such as voice, hair, genitals, libido, supports the maturation of spermatozoids, and the development of bones and muscles.
Everything you always wanted to know about… ♥
When happens the first ejaculation?
It depends on people, but puberty (between 12 and 15 years old) generally marks the beginning of sperm production, genitals growth, and... more frequent random erections!
What are the components of sperm?
Sperm is constituted of several fluids produced by the prostate, the epididymides, the seminal vesicles, and the Cowper's glands.
What are the symptoms of prostate cancer?
At first, prostate cancer doesn't provoke any apparent symptoms, but gradually the urinary and/or ejaculatory functions might be disrupted:
Presence of blood in the urine
Experiencing pain, weak flow, or difficulty urinating
Difficulty retaining urine
Painful ejaculations, or difficulty to hold them back
Pain in the lower back, upper legs, and hips
Prostate cancer hits a vast majority of men above 60 years old. But the good news is that it can be cured easily: the survival rate is nearly 100% when detected early.
Is there such a thing as male menopause?
While it doesn't concern all men, there is a phenomenon called andropause! Some men experience a decrease in desire and testosterone production at some point in their lives, as well as issues with erections, weight gain, insomnia, and hot flashes.
It's relatively rare to hear about andropause, because the scientific community does not unanimously recognize it. Strictly speaking, andropause is not even the equivalent to menopause: indeed, while men remain fertile until death, women can't procreate after menopause.
What is the average penis size?
The dreaded question! The average flaccid penis is around 9,16 cm, while the average erect penis is 13,12 cm. Let's keep in mind that we are all different: big doesn't always mean it's going to feel better!
What is the difference between ejaculation and orgasm?
Ejaculation corresponds to the evacuation of the sperm.
Orgasm is more than that: it accompanies the pelvic floor muscles' contractions, leading to intense pleasure.
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