The ejaculatory ducts (''ductus ejaculatorii'') are paired structures in the

male reproductive system The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body, and within the pelvic cavity, pelvis. The main male sex organs are the hu ...

. Each ejaculatory duct is formed by the union of the

vas deferens The vas deferens (: vasa deferentia), ductus deferens (: ductūs deferentes), or sperm duct is part of the male reproductive system of many vertebrates. In mammals, spermatozoa are produced in the seminiferous tubules and flow into the epididyma ...

with the duct of the seminal vesicle. They pass through the

prostate The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemica ...

, and open into the

urethra The urethra (: urethras or urethrae) is the tube that connects the urinary bladder to the urinary meatus, through which Placentalia, placental mammals Urination, urinate and Ejaculation, ejaculate. The external urethral sphincter is a striated ...

above the

seminal colliculus The seminal colliculus (Latin ''colliculus seminalis''), or verumontanum, of the prostatic urethra is a landmark distal to the entrance of the ejaculatory ducts (on both sides, corresponding vas deferens and seminal vesicle feed into correspondin ...

. During

ejaculation Ejaculation is the discharge of semen (the ''ejaculate''; normally containing sperm) from the penis through the urethra. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. ...

semen Semen, also known as seminal fluid, is a bodily fluid that contains spermatozoon, spermatozoa which is secreted by the male gonads (sexual glands) and other sexual organs of male or hermaphrodite, hermaphroditic animals. In humans and placen ...

passes through the prostate gland, enters the urethra and exits the body via the

urinary meatus The urinary meatus (, ; : meati or meatuses), also known as the external urethral orifice, is the opening of the penis or vulva where urine exits the urethra during urination. It is also where semen exits during male ejaculation, and other fluids ...

Function

Ejaculation

Ejaculation occurs in two stages, the emission stage and the expulsion stage.Rathus, S. A., Nevid, J. S., Fichner-Rathus, L., Herold, E. S. (2010). ''Human Sexuality in a World of Diversity''. Pearsons Education Canada, Pearson Canada Inc. Toronto, ON. The emission stage involves the workings of several structures of the ejaculatory duct; contractions of the prostate gland, the

seminal vesicles The seminal vesicles (also called vesicular glands or seminal glands) are a pair of convoluted tubular accessory glands that lie behind the urinary bladder of male mammals. They secrete fluid that largely composes the semen. The vesicles are 5 ...

, the

bulbourethral gland The bulbourethral glands or Cowper's glands (named for English anatomist William Cowper) are two small exocrine and accessory glands in the reproductive system of many male mammals. They are homologous to Bartholin's glands in females. The bul ...

and the

push fluids into the

prostatic urethra The prostatic urethra, the widest and most dilatable part of the urethra canal, is about 3 cm long. It runs almost vertically through the prostate from its base to its apex, lying nearer its anterior than its posterior surface; the form of ...

. The semen is stored here until ejaculation occurs. Muscles at the base of the penis contract in order to propel the seminal fluid trapped in the prostatic urethra through the penile urethra and expel it through the

. The ejaculate is expelled in spurts, due to the movement of the muscles propelling it. These muscle contractions are related to the sensations of orgasm for the male.

Sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

are produced in the testes and enter the ejaculatory ducts via the vas deferens. As they pass by the seminal vesicles, a fluid rich in fructose combines with the sperm. This addition nourishes the sperm in order to keep them active and motile.Esmail, S. (2010). ''HECOL 211 Human Sexuality Lecture Manual 2010''. Department of Human Ecology, University of Alberta, Edmonton, AB. Seminal fluid continues down the ejaculatory duct into the prostate gland, where an alkaline prostatic fluid is added. This addition provides the texture and odor associated with semen. The alkalinity of the prostatic fluid serves to neutralize the acidity of the female vaginal tract in order to prolong the survival of sperm in this harsh environment. Semen is now a fructose-rich, alkaline fluid containing sperm as it enters the bulbourethral glands below the prostate. The bulbourethral glands secrete a small amount of clear fluid into the urethra before the ejaculate is expelled. The functions of this fluid are not entirely known but are suggested to aid in lubricating the male urethra in preparation for the semen during ejaculation. The amount of semen produced and expelled during ejaculation corresponds to the length of time that the male is sexually aroused before ejaculation occurs. Generally, the longer the period of arousal, the larger the amount of seminal fluid. Ejaculation and

orgasm Orgasm (from Greek , ; "excitement, swelling"), sexual climax, or simply climax, is the sudden release of accumulated sexual excitement during the sexual response cycle, characterized by intense sexual pleasure resulting in rhythmic, involu ...

may occur simultaneously, however they are not coupled, in that one may occur without the other. For example, a man may have a dry orgasm (termed

retrograde ejaculation Retrograde ejaculation occurs when semen which would be ejaculated via the urethra is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts before ejaculation, inhibiting urination and preventing a reflux of semen ...

); there is no expulsion of ejaculate however the man still experiences orgasm. Also, paraplegics may ejaculate seminal fluid but not experience the sensation of orgasm.

Clinical relevance

Ejaculatory duct obstruction

Ejaculatory duct obstruction Ejaculatory duct obstruction (EDO) is a pathological condition which is characterized by the obstruction of one or both ejaculatory ducts. Thus, the efflux of (most constituents of) semen is not possible. It can be congenital or acquired. It is a ...

is an acquired or congenital pathological condition in which one or both ejaculatory ducts are obstructed. In the case that both ejaculatory ducts are obstructed, this illness presents with the symptoms of

aspermia Aspermia is the complete lack of semen with ejaculation (not to be confused with azoospermia, the lack of sperm cells in the semen). It is associated with infertility. One of the causes of aspermia is retrograde ejaculation, because of that the ...

and male

infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...

Benign prostatic hyperplasia

Surgery to correct

benign prostatic hyperplasia Benign prostatic hyperplasia (BPH), also called prostate enlargement, is a noncancerous increase in size of the prostate gland. Symptoms may include frequent urination, trouble starting to urinate, weak stream, urinary retention, inability t ...

may destroy these ducts resulting in

. Retrograde ejaculation empties the seminal fluid formed in the emission phase into the bladder of the male instead of expelling it through the urethra and out the tip of the penis. This results in a dry orgasm, where orgasm may still be experienced but without expulsion of semen from the ejaculatory ducts.

Additional images

File:Illu prostate lobes.jpg, Lobes of prostate File:Gray1156.png, Vertical section of bladder, penis and urethra File:Gray1160.png, Prostate with seminal vesicles and seminal ducts, viewed from in front and above File:Gray1228.png, Median sagittal section of male pelvis File:Prostatic urethra.svg, Dissection of prostate showing ejaculatory ducts opening into the prostatic urethra

References

External links

* - "Lateral (A) and posterior (B) views of the bladder and associated structures." * {{Authority control Mammal male reproductive system Andrology Human penis anatomy