Ejaculatory duct

The ejaculatory ducts (ductus ejaculatorii) are paired structures in the male reproductive system.<ref>Template:Cite book</ref> Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle.<ref>Template:Cite journal</ref> They pass through the prostate, and open into the urethra above the seminal colliculus. During ejaculation, semen passes through the prostate gland, enters the urethra and exits the body via the urinary meatus.<ref name="books.google.co.za">Template:Cite book</ref>

Function

Ejaculation

Template:Main Ejaculation occurs in two stages, the emission stage and the expulsion stage.<ref name="hswd">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.</ref> The emission stage involves the workings of several structures of the ejaculatory duct; contractions of the prostate gland, the seminal vesicles, the bulbourethral gland and the vas deferens push fluids into the prostatic urethra.<ref name="books.google.co.za"/> 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 urinary meatus. 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.<ref>Template:Cite book</ref>

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.<ref name="hslm">Esmail, S. (2010). HECOL 211 Human Sexuality Lecture Manual 2010. Department of Human Ecology, University of Alberta, Edmonton, AB.</ref> Seminal fluid continues down the ejaculatory duct into the prostate gland, where an alkaline prostatic fluid is added.<ref name="hswd" /> This addition provides the texture and odor associated with semen.<ref name="hswd" /> 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.<ref name="hslm" /> Semen is now a fructose-rich, alkaline fluid containing sperm as it enters the bulbourethral glands below the prostate.<ref name="hslm" /> 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.<ref name="hswd" /> The amount of semen produced and expelled during ejaculation corresponds to the length of time that the male is sexually aroused before ejaculation occurs.<ref name="hswd" /> Generally, the longer the period of arousal, the larger the amount of seminal fluid.<ref>Template:Cite web</ref>

Ejaculation and orgasm 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<ref>Retrograde ejaculation treatments</ref>); there is no expulsion of ejaculate however the man still experiences orgasm.<ref name="hswd" /> Also, paraplegics may ejaculate seminal fluid but not experience the sensation of orgasm.<ref name="hswd" />

Clinical relevance

Ejaculatory duct obstruction

Template:Main Ejaculatory duct obstruction is an acquired or congenital pathological condition in which one or both ejaculatory ducts are obstructed.<ref name="0-www.ncbi.nlm.nih.gov.innopac.up.ac.za">Template:Cite journal</ref> In the case that both ejaculatory ducts are obstructed, this illness presents with the symptoms of aspermia and male infertility.<ref name="0-www.ncbi.nlm.nih.gov.innopac.up.ac.za"/><ref>Template:Cite journal</ref>

Benign prostatic hyperplasia

Template:Main Surgery to correct benign prostatic hyperplasia may destroy these ducts resulting in retrograde ejaculation. 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.<ref name="hswd" /> This results in a dry orgasm, where orgasm may still be experienced but without expulsion of semen from the ejaculatory ducts.

Additional images

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  Lobes of prostate
• 
  Vertical section of bladder, penis and urethra
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  Prostate with seminal vesicles and seminal ducts, viewed from in front and above
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  Median sagittal section of male pelvis
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  Dissection of prostate showing ejaculatory ducts opening into the prostatic urethra

See also

• Excretory duct of seminal gland
• Seminal vesicles
• Prostate

External links

• Template:SUNYAnatomyFigs - "Lateral (A) and posterior (B) views of the bladder and associated structures."
• Template:DartmouthHumanAnatomy