WordNet

a continuous tube formed by a row of elongated cells lacking intervening end walls
an enclosed conduit for a fluid
a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance; "the tear duct was obstructed"; "the alimentary canal"; "poison is released through a channel in the snakes fangs" (同)epithelial duct, canal, channel
a man who ejaculates semen
a speaker who utters a sudden exclamation

PrepTutorEJDIC

送水管;(建物・船などの)通気管;(地下ケーブルなどの)ダクト / (体液を運ぶ)導管,(植物が水・空気を運ぶ)導管

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/08/02 01:34:48」(JST)

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The ejaculatory ducts (ductus ejaculatorii) are paired structures in male anatomy.^[1] Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle.^[2] They pass through the prostate, and open into the urethra at the Colliculus seminalis. During ejaculation, semen passes through the prostate gland, enters the urethra and exits the body via the tip of the penis.^[3]

Function

Ejaculation

Dissection of prostate showing ejaculatory ducts opening into the prostatic urethra.

Ejaculation occurs in two stages, the emission stage and the expulsion stage.^[4] 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.^[3] 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 tip of the penis. 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.^[5]

Sperm is produced in the testes and enters the ejaculatory ducts via the vas deferens. As it passes by the seminal vesicles, a fluid rich in fructose combines with sperm. This addition nourishes the sperm in order to keep it active and motile.^[6] Seminal fluid continues down the ejaculatory duct into the prostate gland, where an alkaline prostatic fluid is added.^[4] This addition provides the texture and odor associated with semen.^[4] 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.^[6] Semen is now a fructose-rich, alkaline fluid containing sperm as it enters the bulbourethral glands below the prostate.^[6] 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.^[4] The amount of semen produced and expelled during ejaculation corresponds to the length of time that the male is sexually aroused before ejaculation occurs.^[4] Generally, the longer the period of arousal, the larger the amount of seminal fluid.^[7]

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^[8]); there is no expulsion of ejaculate however the man still experiences orgasm.^[4] Also, paraplegics may ejaculate seminal fluid but not experience the sensation of orgasm.^[4]

Clinical relevance

Ejaculatory duct obstruction

Ejaculatory duct obstruction is an acquired or congenital pathological condition in which one or both ejaculatory ducts are obstructed.^[9] In the case that both ejaculatory ducts are obstructed, this illness presents with the symptoms of aspermia/azoospermia and male infertility.,^[9]^[10]

Benign prostatic hyperplasia

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.^[4] This results in a dry orgasm, where orgasm may still be experienced but without expulsion of semen from the ejaculatory ducts.

Additional images

Lobes of prostate
Vertical section of bladder, penis and urethra.
Prostate with seminal vesicles and seminal ducts, viewed from in front and above.
Median sagittal section of male pelvis.

References

^ http://books.google.co.za/books/about/Handbook_of_andrology.html?id=AAtrAAAAMAAJ&redir_esc=y
^ http://www.asiaandro.com/archive/1008-682X/3/251.htm
^ ^a ^b https://books.google.co.za/books?id=mEgckDNkonUC&printsec=frontcover&dq=Andrology:+Male+Reproductive+Health+and+Dysfunction&hl=en&sa=X&ei=g1gvVa-RGYjsO9SFgEA&ved=0CCUQ6AEwAA#v=onepage&q=Andrology%3A%20Male%20Reproductive%20Health%20and%20Dysfunction&f=false
^ ^a ^b ^c ^d ^e ^f ^g ^h 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.
^ https://books.google.co.za/books?id=eCxSycu3TBUC&printsec=frontcover&dq=Human+Reproductive+Biology&hl=en&sa=X&ei=7FwvVempNubRygPCzICACg&ved=0CCMQ6AEwAQ#v=onepage&q=Human%20Reproductive%20Biology&f=false
^ ^a ^b ^c Esmail, S. (2010). HECOL 211 Human Sexuality Lecture Manual 2010. Department of Human Ecology, University of Alberta, Edmonton, AB.
^ http://andrologysociety.org/Andrology-Press/Andrology-Handbook,-2nd-Edition.aspx
^ http://www.fertilityfactor.com/infertility_male_infertility_retrograde_ejaculation.html Retrograde ejaculation treatments
^ ^a ^b http://0-www.ncbi.nlm.nih.gov.innopac.up.ac.za/pubmed/23733548
^ http://0-www.ncbi.nlm.nih.gov.innopac.up.ac.za/pubmed/17055837

External links

Anatomy figure: 44:03-15 at Human Anatomy Online, SUNY Downstate Medical Center - "Lateral (A) and posterior (B) views of the bladder and associated structures."
figures/chapter_34/34-3.HTM — Basic Human Anatomy at Dartmouth Medical School

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 男性不妊症の評価 evaluation of male infertility
2. 男性の性交時痛 male dyspareunia
3. 男性不妊症の治療 treatment of male infertility
4. 血精液症 hematospermia

English Journal

New Austrognathiidae (Gnathostomulida: Conophoralia) from Hong Kong and Japan: microscopic anatomy, ultrastructure and evolutionary implications.

Achatz JG1, Sterrer W2.
Zootaxa.Zootaxa.2015 May 4;3955(2):267-82. doi: 10.11646/zootaxa.3955.2.5.
We describe two new species, Austrognathia glandifera and Austrognatharia orientis using observations on squeezed, live specimens as well as histological sections and transmission electron microscopy. The protonephridia of Austrognatharia orientis are composed of a terminal cell, a canal cell, and a
PMID 25947850

Morphological alterations of all stages of spermatogenesis and acrosome reaction in Chinese mitten crab Eriocheir sinensis.

Wang YL1, Sun WJ, He L, Li Q, Wang Q.
Cell and tissue research.Cell Tissue Res.2015 May;360(2):401-12. doi: 10.1007/s00441-014-2092-5. Epub 2015 Feb 4.
The Chinese mitten crab (Eriocheir sinensis) is a seasonally breeding species and its reproductive system comprises paired symmetrical structures: testes, vasa deferentia, seminal vesicles, accessory glands and ejaculatory ducts. Histological examination of the testis of mature males reveals regress
PMID 25648553

Transurethral endoscopic treatment of seminal vesicle cysts (report of seven cases).

Wang MS1, Li BJ, Huang ZM, Luo Y, Zhang Y, Li K, Zhang KQ, Jin FS, Li YF.
International urology and nephrology.Int Urol Nephrol.2015 May;47(5):717-21. doi: 10.1007/s11255-015-0944-x. Epub 2015 Mar 21.
OBJECTIVE: Seminal vesicle cysts are a rare disorder of the male reproductive system. The goal of this report was to summarize the radiological manifestations and transurethral endoscopic treatment of large seminal vesicle cysts.MATERIALS AND METHODS: The clinical data of seven cases of giant semina
PMID 25794499

Japanese Journal

間隙性貝形虫類(甲殻類)における性選択と進化(2009年度日本動物分類学会シンポジウム)

田中隼人
タクサ : 日本動物分類学会誌 (28), 17-22, 2010-02-20
… The shapes of male ejaculatory duct are divided into the three types i.e., a helical tube type (Type H), a curved short tube type (Type S), and tapering long tube type (Type L). … The rod-shaped structure is thought as a part of the male copulatory duct. … According to this, the extremely long type of copulatory duct must have evolved gradually from the short curved tube type. …
NAID 110008511463

ミューラー管嚢胞と射精管閉塞に対する経会陰的内視鏡治療の1例

岡部勉,吉住修,金城満
西日本泌尿器科 68(11), 552-555, 2006-11-20
NAID 10018657336

Related Pictures

★リンクテーブル★

リンク元	「射精管」
関連記事	「duct」「ejaculatory」

「射精管」

Ejaculatory duct
	Male Anatomy
	Vesiculæ seminales and ampullæ of ductus deferentes, seen from the front. The anterior walls of the left ampulla, left seminal vesicle, and prostatic urethra have been cut away.
Details
Latin	Ductus ejaculatorius (Plural: Ductus ejaculatorii)
Identifiers
Gray's	p.1247
MeSH	A05.360.444.251
FMA	19325
	Anatomical terminology