The Male Reproductive System – Participating Structures

There may possibly be more information here than you ever wanted to know about the reproductive system of the human male. But I think that if you’re going to play with a complex, pretty, and valuable toy, it makes sense to me to figure out how it works, so it doesn’t, like, um, get broken accidentally somehow.

(or even to know if it started out broken, so you know whether you should take it back and get it fixed, or replaced under warranty, or whatever)

And if you’re going to play with something this delicate, I think it makes sense to know how it’s normally supposed to work without any, um, interference I mean influences, say, like, being broken or something.

For the purpose of this guide, and for ease of explanation, I am going to introduce Eric, an imaginary man I made up, who is the person behind the reproductive system.
 

Because I think it’s vitally important to remember that every human reproductive system has a human being behind it. :)

 
And for the same reasons, I am going to give Eric a predilection for linoleum, because he will need something to excite him so we can see how his reproductive system works.

So, here are the facts about Eric’s reproductive structures, with a special perspective on milking skillfully woven into them (I hope). :)
 
 

Anatomy – Participating Physical Structures

Every normal male reproductive system, like Eric’s, is (apparently) comprised of four main parts: the testicles, the duct system, the gland systems, and the penis.
 
Trust a group of men to classify their own reproductive system by making their penis and testicles into entire whole categories all by themselves. ;)
 

                              Eric’s Reproductive System

 
 
The Testes
 
The testicles are considered the main reproductive organ when it comes to Eric’s fertility. This is because the testes help produce the male sex hormone testosterone as well as producing sperm.
 

                                                          Eric’s Testis

 

• The testicles (testes, singular testis) are the two, oval-shaped organs located within Eric’s scrotum, which is a muscular sac that protects the testes and regulates their temperature. Eric’s testes are made up of seminiferous tubules comprised of hundreds of tiny tubes, interstitial (Leydig) cells which produce testosterone, and Sertoli cells which nurture immature sperm cells. As Eric’s testicles begin to produce testosterone, sperm cells located within tiny tubes begin to divide. Eventually, these immature sperm cells will move into the epididymis.

  Both sperm and testosterone production occur in the testes, which are contained in the scrotal sac (the scrotum). This sac develops on the outside of the body because normal body temperature is too high to allow sperm production.

 
 
The Duct System
 
Eric’s duct system, as in every normal male, is comprised of several tubes which transport fluids within the male reproductive system. These tubes are necessary to keep sperm healthy and motile (moving well).
 

• Eric’s epididymis will be found curving around the top of his testis. It’s a remarkable C-shaped tube, 1/300 of an inch in diameter and about 20 feet long. It loops back and forth on itself within a space that is only about one and a half inches long. Eric’s epididymis receives sperm from the seminiferous tubules in his testis. The epididymis has three parts: a head, body, and tail. The epididymis stores sperm and propels it toward Eric’s penis. Smooth muscle contractions in the epididymis walls move Eric’s sperm through the duct. As sperm pass through the epididymis, the sperm mature and receive nourishment. The sperm’s journey through the epididymis takes about three weeks.

 

• Eric’s vasa deferentia are long, rigid and wire-like muscular channels. A single channel is called a vas deferens. The vas deferens travels out of Eric’s scrotum and into his lower abdomen, passes behind his urinary bladder in the pelvic cavity, and expands to form an ampulla (expanded end part). Each ampulla joins with a seminal vesicle (an accessory gland behind the base of the urinary bladder) to form an ejaculatory duct. Eric’s vas deferens is his main sperm carrier. Its walls contain three layers of smooth muscle triggered into action by nerves working together in synergy. Stimulation of these nerves propels sperm into the ejaculatory ducts.
   
  In short – the vas deferens transports mature sperm to the ejaculatory ducts in preparation for ejaculation through the urethra.

 

• Eric’s ejaculatory ducts are located behind the base of his bladder, below the junction where each ampulla vas deferens and seminal vesicle come together, and are surrounded by his prostate. Eric’s ejaculatory ducts store his semen whilst receiving more secretions from his seminal vesicles. Eric’s ejaculatory ducts drain through his prostate gland into his bulbous urethra (an enlarged section of his urethra near the bulbourethral glands), where his semen is combined with further seminal fluid from his prostate gland and bulbourethral glands. And from there, Eric’s semen is ejaculated (after he’s been exciting himself over that kinky linoleum catalogue).

 

• Eric’s urethra is the final section of his duct system. It is a tiny tube which extends from Eric’s urinary bladder and the ends of his ejaculatory ducts (at which point it is called the bulbous urethra), through his prostate gland and into his penis, terminating in a small opening at the end of his penis from which his semen is released. Eric’s urethra receives secretions from his ejaculatory ducts, prostate gland, and bulbourethral glands (accessory glands). Eric’s semen is comprised of sperm, as well as fluids added to his sperm by his prostate and other glands. Eric’s semen passes through his urethra and is expelled during ejaculation. His urethra also carries urine through it from his bladder during urination. However, Eric’s urethra, like every male urethra, cannot carry both fluids simultaneously. Prior to ejaculation, a muscular sphincter (ring of muscle) in Eric’s prostate closes off his bladder.

 
 
The Gland System
 
Eric’s gland system secretes seminal fluids which mix with sperm in order to nourish them, help them develop, and help them move faster. This mixture of fluids (ejaculate) are released when Eric ejaculates.
 

• Eric’s seminal vesicles are two pouch-like sacs which are located behind the base of his bladder. They are clusters of tissue which secrete an alkaline (base), fructose rich fluid which accounts for 30% of the semen Eric releases during ejaculation. This is combined with his sperm before they enter the urethra, and provides spermal nourishment. Add the fluid secreted from the nearby prostate gland later on, and this mixture of various fluids and sperm comprises Eric’s semen.

 

• Eric’s prostate is a walnut-shaped gland which is situated just below his bladder. Eric’s prostate surrounds his ejaculatory ducts and urethra, and with a ring of smooth muscle, ensures that only semen OR urine passes through his urethra, and never both. Prostatic fluid comprises 60% of fluid Eric releases as semen, and drains into his bulbous urethra via its own personal private prostatic duct. Prostatic fluid helps nourish and protect Eric’s sperm by neutralising any vestigial acidity not already taken care of by the secretions from his bulbourethral glands.

 

• Eric’s bulbourethral glands, or Cowper’s glands, are pea-sized structures located alongside his bulbous urethra just below his prostate gland. These glands secrete a clear, slippery, alkaline fluid which comprises 5% of Eric’s ejaculate. This fluid empties directly into Eric’s urethra, lubricates it, and neutralises acidity from any residual drops of urine.

  This fluid might be recognised by some as pre-ejaculate, or “pre-come“.

 
There’s more on some of Eric’s other participating glands below.
 
 
The Penis
 
Eric’s penis is the delivery system for his sperm, as well as being the exit route for his urine. Thanks to Eric’s prostate, however, it cannot serve as a conduit for both at the same time.
 

                                                          Eric’s Penis

 

• Eric’s penis is comprised of three parts: the head (glans penis), the root, and the shaft. The penis is made up of veins, arteries, and spongy tissue. The urethra traverses the shaft and its opening (known as the meatus), lies at the tip of the glans penis. Eric’s penis is a passage both for urine and for the ejaculation of semen (but not at the same time).

  When Eric is sexually aroused (say, from, like, looking at linoleum), his penis becomes erect. The primary physiological mechanism responsible for Eric’s erection is the autonomic dilation of his arteries supplying blood to his penis. This dilation allows increased blood flow to the three spongy erectile tissue chambers in Eric’s penis. His penis lengthens and stiffens as it fills with blood. Eric’s now-engorged erectile tissue presses against and constricts the veins that carry blood away from the penis.
   

  (but Eric won’t necessarily be thinking about that what with being so excited about this season’s new linoleum and all)

   
  So more inward blood flow results in more stiffness, and more stiffness increasingly restricts outward blood flow. This means more blood comes in than goes out. Obviously this cannot go on indefinitely. At some point, a certain degree of stiffness leads to a balance between the volume of blood flow in through the dilated arteries, and out through the constricted veins. So, the design specs of Eric’s penis result in a maximum maintainable erectile size when this balance is reached.

  (that is, until somebody messes with things by tying stuff around the base of the penis and waiting to see what happens)

  (and so I’m told, obviously, I would never do such a thing myself, obviously)

So those are the four main parts of Eric’s reproductive system. But wait! There’s more! (believe it or not)
 
 

Endocrinology – Hormones

                                                          Eric’s Brain

 
Copyleft and © 2002-2008 Steve Cook.     Thank you Steve. :)
 
 
Eric’s endocrine system consists of several glands, in different parts of his body. In the case of the reproductive endocrinology of the horny I mean human male such as Eric, some of his relevant glands are:
 

• Seminal vesicles (Excretory duct of seminal gland)
• Prostate (Urethral crest/Seminal colliculus/Prostatic utricle/Ejaculatory duct, Prostatic sinus/Prostatic ducts)
• Bulbourethral glands (Cowper’s glands)

  (those three were mentioned above already)

• Hypothalamus
• Pituitary
• Gonads (testes in this case)

  (and yes, Eric’s testes function as glands as well as organs, how’s that for confusing?)

 
Since Eric’s hypothalamus, pituitary, and gonads all function cooperatively for the purposes of reproduction, they are commonly referred to as a single unit – his hypothalamic-pituitary-gonadal axis.
 

(try having a few drinks and saying that one three times fast)

 
One of the features about most of Eric’s glands which make them different from other organs in the body, is that, for the most part, they secrete hormones directly into Eric’s blood, instead of into a duct system as the glands mentioned above do.

Hormones are molecules which act as signals from one type of Eric’s cells to another. Most hormones reach their targets via the blood.

Hormones do lots of stuff, and do it in lots of different ways. One hormone (such as testosterone) may have several effects (body hair, sperm production) on different target organs (skin, testes). Conversely, one target organ (the testes) may be affected by more than one hormone (testosterone, follicle stimulating hormones [FSH]).
 
 

Moving On – So How Does All This Stuff Work?

Ok, that’s enough of that. Now, what does all this hormone stuff have to do with Eric’s reproductive system?

Well, the thing is, Eric’s fertility would just be a total non-starter if he didn’t have a properly functional endocrine system.

We actually are slaves to our hormones. It’s official. ;)

If you want to find out how all this information comes together to produce an ejaculation, you may read all about it here. :)