Vas deferens - wikipedia Vas deferens This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( March 2013 ) Vas deferens Male Anatomy Vertical section of the testis, to show the arrangement of the ducts. Details Precursor Wolffian duct Artery Superior vesical artery, artery of the ductus deferens Lymph External iliac lymph nodes, internal iliac lymph nodes Identifiers Latin Vas deferens ( plural : vasa deferentia ), Ductus deferens ( plural : ductus deferentes ) MeSH A05. 360.444. 930 FMA 19234 Anatomical terminology ( edit on Wikidata ) Vas deferens The vas deferens ( Latin : `` carrying - away vessel '' ; plural : vasa deferentia ), also called ductus deferens ( Latin : `` carrying - away duct '' ; plural : ductus deferentes ), is part of the male reproductive system of many vertebrates ; these vasa transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. It is a partially coiled tube which ascends into the abdomen through the inguinal canal. Contents 1 Structure 1.1 Blood supply 2 Function 3 Clinical significance 3.1 Contraception 3.2 Disease 3.3 Uses in pharmacology and physiology 4 Other animals 5 Additional images 6 See also 7 References 8 External links Structure There are two ducts, connecting the left and right epididymis with the seminal vesicles to form the ejaculatory duct in order to move sperm. In humans, each tube is about 30 centimeters ( 1 ft ) long, 3 to 5 mm in diameter and is muscular ( surrounded by smooth muscle ). Its epithelium is pseudostratified columnar epithelium lined by stereocilia. They are part of the spermatic cords. Blood supply The vas deferens is supplied by an accompanying artery ( artery of vas deferens ). This artery normally arises from the superior ( sometimes inferior ) vesical artery, a branch of the internal iliac artery. Function During ejaculation, the smooth muscle in the walls of the vas deferens contracts reflexively, thus propelling the sperm forward. This is also known as peristalsis. The sperm is transferred from the vas deferens into the urethra, collecting secretions from the male accessory sex glands such as the seminal vesicles, prostate gland and the bulbourethral glands, which form the bulk of semen. Clinical significance Contraception The procedure of deferentectomy, also known as a vasectomy, is a method of contraception in which the vasa deferentia are permanently cut, though in some cases it can be reversed. A modern variation, which is also known as a vasectomy even though it does not include cutting the vas, involves injecting an obstructive material into the ductus to block the flow of sperm. Investigational attempts for male contraception have focused on the vas with the use of the intra vas device and reversible inhibition of sperm under guidance. Disease The vas deferens may be obstructed, or it may be completely absent in a condition known as congenital absence of the vas deferens ( CAVD, a potential feature of cystic fibrosis ), causing male infertility. Acquired obstructions can occur due to infections. To treat these causes of male infertility, sperm can be harvested by testicular sperm extraction ( TESE ), microsurgical epididymal sperm aspiration ( MESA ), or other methods of collecting sperm cells directly from the testicle or epididymis. Uses in pharmacology and Physiology. The vas deferens has a dense sympathetic innervation, making it a useful system for studying sympathetic nerve function and for studying drugs that modify neurotransmission. It has been used : as a bioassay for the discovery of enkephalins, the endogenous opiates. to demonstrate quantal transmission from sympathetic nerve termianals. as the first direct measure of free Ca concentration in a postganglionic nerve terminal. to develop an optical method for monitoring packeted transmission ( similar to quantal transmission ). Other animals Most vertebrates have some form of duct to transfer the sperm from the testes to the urethra. In cartilaginous fish and amphibians, sperm is carried through the archinephric duct, which also partially helps to transport urine from the kidneys. In teleosts, there is a distinct sperm duct, separate from the ureters, and often called the vas deferens, although probably not truly homologous with that in humans. In cartilaginous fishes, the part of the archinephric duct closest to the testis is coiled up to form an epididymis. Below this are a number of small glands secreting components of the seminal fluid. The final portion of the duct also receives ducts from the kidneys in most species. In amniotes, however, the archinephric duct has become a true vas deferens, and is used only for conducting sperm, never urine. As in cartilaginous fish, the upper part of the duct forms the epididymis. In many species, the vas deferens ends in a small sac for storing sperm. The only vertebrates to lack any structure resembling a vas deferens are the primitive jawless fishes, which release sperm directly into the body cavity, and then into the surrounding water through a simple opening in the body wall. Additional images Male reproductive system. Coronal section of pelvis, showing arrangement of fasciæ. Viewed from behind. The relations of the femoral and abdominal inguinal rings, seen from within the abdomen. Right side. The spermatic cord in the inguinal canal. Fundus of the bladder with the vesiculæ seminales. Vertical section of bladder, penis, and urethra. Prostate with seminal vesicles and seminal ducts, viewed from in front and above. Prostate Microscopic cross section. Testis, spermatic vessels and vas deferens A deep dissection showing the vas deferens. See also This article uses anatomical terminology ; for an overview, see Anatomical terminology. Vasectomy Intra vas device Excretory duct of seminal gland vas deferens in the reproductive system of gastropods References Jump up ^ Dr C Sharath Kumar, Ph D Thesis, University of Mysore, 2013 Jump up ^ Sjöstrand, N.O. ( 1965 ). `` The adrenergic innervation of the vas deferens and the accessory male genital organs ''. Acta Physiologica Scandinavica. 257 : S1 -- 82. Jump up ^ Burnstock, G ; Verkhratsky, A ( 2010 ). `` Vas deferens -- a model used to establish sympathetic cotransmission ''. Trends in Pharmacological Sciences. 31 ( 3 ) : 131 -- 9. PMID 20074819. doi : 10.1016 / j. tips. 2009.12. 002. Jump up ^ Hughes, J ; Smith, T.W. ; Kosterlitz, H.W. ; Fothergill, L.A. ; Morgan, B.A. ; Morris, H.R. ( 1975 ). `` Identification of two related pentapeptides from the brain with potent opiate agonist activity ''. Nature. 258 ( 5536 ) : 577 -- 80. PMID 1207728. doi : 10.1038 / 258577a0. Jump up ^ Brock, J.A. ; Cunnane, T.C. ( 1987 ). `` Relationship between the nerve action potential and transmitter release from sympathetic postganglionic nerve terminals ''. Nature. 326 ( 6113 ) : 605 -- 7. PMID 2882426. doi : 10.1038 / 326605a0. Jump up ^ Brain, K.L. ; Bennett, M.R. ( 1997 ). `` Calcium in sympathetic varicosities of mouse vas deferens during facilitation, augmentation and autoinhibition ''. The Journal of Physiology. 502 ( 3 ) : 521 -- 36. PMC 1159525. PMID 9279805. doi : 10.1111 / j. 1469 - 7793.1997. 521bj. x. Jump up ^ Brain, K.L. ; Jackson, V.M. ; Trout, S.J. ; Cunnane, T.C. ( 2002 ). `` Intermittent ATP release from nerve terminals elicits focal smooth muscle Ca2+ transients in mouse vas deferens ''. The Journal of Physiology. 541 ( Pt 3 ) : 849 -- 62. PMC 2290369. PMID 12068045. doi : 10.1113 / jphysiol. 2002.019612. ^ Jump up to : Romer, Alfred Sherwood ; Parsons, Thomas S. ( 1977 ). The Vertebrate Body. Philadelphia, PA : Holt - Saunders International. pp. 393 -- 395. ISBN 0 - 03 - 910284 - X. External links Wikimedia Commons has media related to Vas deferens. Anatomy photo : 36 : 07 - 0301 at the SUNY Downstate Medical Center -- `` Inguinal Region, Scrotum and Testes : Layers of the Spermatic Cord '' Anatomy photo : 44 : 02 - 0301 at the SUNY Downstate Medical Center -- `` The Male Pelvis : Distribution of the Peritoneum in the Male Pelvis '' Medical Mnemonics.com : 2424 319 Cross section image : pelvis / pelvis - e12 - 15 -- Plastination Laboratory at the Medical University of Vienna inguinalregion at The Anatomy Lesson by Wesley Norman ( Georgetown University ) ( testes ) Male reproductive system Internal Seminal tract Testes layers Tunica vaginalis Tunica albuginea Tunica vasculosa Appendix Mediastinum Lobules Septa Leydig cell Sertoli cell Blood -- testis barrier Spermatogenesis Spermatogonium Spermatocytogenesis Spermatocyte Spermatidogenesis Spermatid Spermiogenesis Spermatozoon Other Seminiferous tubules Tubuli seminiferi recti Rete testis Efferent ducts Epididymis Appendix Stereocilia Paradidymis Spermatic cord Vas deferens Ampulla Ejaculatory duct Accessory glands Seminal vesicles excretory duct Prostate Urethral crest Seminal colliculus Prostatic utricle Ejaculatory duct Prostatic sinus Prostatic ducts Bulbourethral glands External Penis root Crus Bulb Fundiform ligament Suspensory ligament body Corpus cavernosum Corpus spongiosum glans Foreskin Frenulum Corona fascia superficial deep Tunica albuginea Septum of the penis Urinary tract Internal urethral orifice Urethra Prostatic Intermediate Spongy Navicular fossa External urethral orifice Lacunae of Morgagni Urethral gland Scrotum layers skin Dartos External spermatic fascia Cremaster Cremasteric fascia Internal spermatic fascia Perineal raphe Scrotal septum Retrieved from `` https://en.wikipedia.org/w/index.php?title=Vas_deferens&oldid=789405855 '' Categories : Mammal male reproductive system Scrotum Hidden categories : Articles needing additional references from March 2013 All articles needing additional references Medicine infobox template using GraySubject or GrayPage Commons category template with no category set Commons category without a link on Wikidata All articles with dead external links Articles with dead external links from November 2015 Talk Contents About Wikipedia Bosanski Català Čeština Cymraeg Deutsch ދިވެހިބަސް Eesti Español Esperanto فارسی Français Galego 한국어 हिन्दी Hrvatski Bahasa Indonesia Italiano עברית Latina Lietuvių Nederlands 日本 語 Plattdüütsch Polski Português Română Русский Scots Simple English Slovenčina Slovenščina کوردی Srpskohrvatski / српскохрватски Suomi Svenska Tagalog தமிழ் Татарча / tatarça తెలుగు Українська 粵語 中文 Edit links This page was last edited on 7 July 2017, at 03 : 57. 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Question: when are spermatozoa transported from the vas deferens to the abdominal urethra
Answer: ejaculation