MALE ANATOMY OF THE
REPRODUCTIVE SYSTEM

Visual Aid, Glossary of Definitions, and Explanations

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Definitions are documented in a counter-clockwise order (from bladder to sigmoid colon).

Bladder: A sac-like organ composed of musculomembranous fiber. Located in the pelvis, the bladder stores urine until it is excreted. The urine is passed to the bladder through ureters from each kidney in peristaltic (contractile) waves. During excretion, the urethral orifice below the bladder is opened and the urine passes through the urethra. Though the urge to void the bladder of urine generally occurs when it has about 250 - 300 milliliters (8 - 10 ounces) in it, the average human bladder can hold almost twice this amount. An average human excretes one to two quarts (or one to two liters) of urine per day, though this is greatly dependent upon the health, diet, and level of activity of the adult. Ingested water usually is excreted within four hours of ingestion. Urine is usually clear or yellow, though this depends upon the diet and health of the individual. Urine has a distinct, ammonia-like smell which is primarily due to the nitrogenous wastes which make up 5 % of the urine. The chief constituent of these wastes is urea, though ammonia, uric acid, creatinine, and a host of other waste products also are present.

Pubic Bone: Part of the skeletal system undreneath the pubic hair area, above the penis.

Penis: The male sex organ that carries urine and semen from the male body, which is capable of erection by becoming engorged with blood during sexual arousal to make it more firm for penetration in sexual intercourse. The penis supports the urethra as it passes from the seminal vesicles, through the corpora cavernosa, to the meatus (opening) at the glans (head) of the penis.

Corpora Cavernosa: Made of spongy tissue which fill with blood during sexual arousal. As the blood fills these tissues, the penis begins to expand and become firm, and this condition is known as an erection. The erection facilitates the ejaculational transport of the semen to the female's vagina.

Penis Glans: Enlarged tip, or head, of the penis. In its apex is the vertical meatus, or opening, of the urethra.

Foreskin: A loose fold of skin, or prepuce, which covers the glans of the penis. It is often removed from infants for sanitary and religious reasons. The removal of the foreskin is known as circumcision.

Urethra: A tube-like vessel that serves to transport urine and semen, conveying it from the bladder or testes through the penis.

Urethral Opening: The penis opening, or meatus.

Scrotum: The protective skin pouch which contains the testes (testicles). It is located in the groin, on the outside of the abdominal cavity. This positioning allows the testicles to remain at a temperature slightly below body temperature, a critical condition in the development of viable sperm. After puberty, the hair begins to grow on the scrotum and nearby skin. This pubic hair remains for the rest of the adult life.

Epididymides: (plural for epididymis) Narrow, elongated storage vessels for newly generated sperm. They are located within the scrotum, adjoining each testicle. Sperm remain in the cord-like epididymides until ejaculation, at which time they eject them into the vas deferens.

Vas Deferens: The narrow continuation of the canal of the epididymis, serving to transport the sperm cells from the epididymis, up through a canal toward the bladder, and then to the ejaculatory duct.

Anus: The opening where solid waste is excreted.

Cowper's Glands: (also known as bulbourethral glands) The two pea-sized lobes connecting to the side of the urethra, responsible for secreting a lubricant into the urethra to facilitate the transport of sperm during ejaculation. This lubricant is frequently referred to as "pre-cum" in English slang.

Prostate Gland: Responsible for secreting a fluid into the urethra during sexual arousal. This alkaline fluid comes before the sperm cells and helps reduce the acidity of vaginal secretions, so that the sperm cells are not destroyed by this acidity. The prostate gland is about 1½ inches in diameter.

Ejaculatory Duct: Short tubule located just above the prostate gland. It is formed by the connection of the vas deferens and the seminal vesicles, and serves to transport sperm through the prostate gland and into the urethra.

Seminal Vesicles: Responsible for secreting a fluid component of semen as the sperm cells pass through the vas deferens. The two vesicles resemble small, bulbous pouches and are located just above the prostate gland.

Rectum: One of the last portions of the large intestine, which extends from the sigmoid colon to join the anal canal. Fecal wastes are stored in the rectum until they are expelled by passing them through the anal canal and out of the anus. The rectum is about five inches long,

Sigmoid Colon (spelled as sigismoid colon above): Connects the end of the descending colon to the rectum. The rectal and sigmoid sections are often referred to as the rectosigmoid.
Special thanks to Mythos / WebMD Anatomy.

Additional Information Provided by the Public:

SEXUALITY: Heterosexual
GENDER: Male
TITLE: bobby

I have nothing to add at this point. This section appears accurate and honest. It appears you have everything covered thus far.

Editor's Note: Thank you

In all these lists of the male anatomy I've never seen the Cresmaster Muscle being mentioned. I know all about it as it causes me great pain and discomfort. What is it? Where is it? You may ask. Simply, it's the muscle(s) that causes your testicle (testis) to retract during ejaculation, cold things and scares. I've been living for the past year with a cresmaster muscle that spasmed. When my scrotum is loose it causes the right testicle to hang verically rather than horizontally. Then when it tightens it pulls the testicle right in tight below the penis causing pain to the testicle and the pain from the tightened cresmaster muscle runs though your groin to your hip. When I was refered to a surgeon he didn't know what it was that was causing the spasm. It was only after I saw a urologist that he told me what it was. I never heard of it. A senior surgeon says the cannot operate on it as the muscle is too delicate in a delicate area. But an ultra sound found the testicle is healthy. I can't have sex, masturbate or even walk too far without causing me pain. So I think after all that it is definitely worth mentioning as part of the male anatomy.

Editor's Note: Thank you for the additional information! We will try to investigate this more in the future.

SEXUALITY: Heterosexual
GENDER: Male
TITLE: Getting the anatomy right - Paul B.

Sorry guys, but I'm a "stickler" for detail. -----

There are certain common blunders in the description of the diagram above. The most important, is in regard to the Epididymis (or plural thereof) where it is stated "Sperm remain in the cord-like epididymides until ejaculation, at which time they eject them into the vas deferens." This, and the popular fantasy on the various wank sites, that a guy "feels the cum rising from his balls", is complete nonsense, which is important to realise for a couple of reasons, notably that after vasectomy which cuts the vasa deferentia just above the epididymides, it takes (about) ten ejaculations or three months for the sperm stored in the vasa deferentia to be "purged" and for the man to actually become infertile. Very important to know! -----

So, what is the true story? Well, it's blindingly obvious in the diagram! Note the part of the vas deferens shown immediately in front of the seminal vesicles (and shown overlaying the diagrammatically "cut" bladder wall)? There is clearly a bulge in it, called the "ampulla" of the vas deferens - this is the actual storage area for the sperm and in real life, it is (they - two - are) sitting right alongside the seminal vesicles and the ejaculatory ducts consist of the four connections between the two ampullae plus the two seminal vesicles, and the prostate. It is through these ducts that the sperm and half the semen are pumped into the urethra to combine with the other half of the semen that is contributed by the prostate, which provides the most pleasurable feeling of "filling" or "inevitability" just before (and continuing as) contractions of the bulbocavernosus muscle forcibly compress the "bulb" of the penis and the resulting pressure wave(s) travelling along the corpus spongiosum (both shown but not annotated on the diagram) eject successive spurts of semen. -----

In actual fact, the vasa deferentia up to the ampullae are so narrow that it actually takes days or weeks for the sperm to get from the Epididymis to the ampulla despite how ever much "hurry up" occurs during sexual excitement. -----

Next problem - the confusion between prostatic and Cowper's gland secretions. The prostate gland produces (approximately) half the semen (and note by the way that the sperm constitute an almost insignificant proportion, less than one percent, so their presence or absence is undetectable without a microscope) and this certainly includes the alkaline "buffer" to protect the sperm from acid urine remnants, but this is not released until (the start of) ejaculation. -----

"Pre-cum" (pre-ejaculate) is produced by the Cowper's and para-urethral (all along the urethra) glands specifically during sexual excitement (in contrast to erection, which may result from various physical stimuli, but is not a pre-requisite for producing "pre-cum") and whilst it does tend to "flush out" the urethra, there is no real need for it to "facilitate the transport of sperm during ejaculation"; its primary purpose is clearly to provide lubrication for sexual activity, adding to vaginal secretions. -----

And incidentally, unless the remnant from a previous ejaculation has yet to be flushed out by urination, "pre-cum" does not contain viable sperm (that is, risk of pregnancy) - since it is not from the prostate or seminal apparatus.

Editor's Note: Thank you for the additional information! We will try to investigate this more in the future. Except for the last part, which was deleted because 99.9% of our readers are not going to look up the word "pecuniary".

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