Vas deferens
 | This articleneeds additional citations forverification.(March 2013) |
| Vas deferens | |
|---|---|
 Vertical section of thetestis,to show the arrangement of the ducts | |
| Details | |
| Precursor | Mesonephric ducts |
| 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 | D014649 |
| TA98 | A09.3.05.001 |
| TA2 | 3621 |
| FMA | 19234 |
| Anatomical terminology | |
Thevas deferens(pl.:vasa deferentia),ductus deferens(pl.:ductūs deferentes), orsperm ductis part of the malereproductive systemof manyvertebrates.The vasa deferentia are pairedsex organsthat transportspermfrom theepididymidesto theejaculatory ductsin anticipation ofejaculation.The vas deferens is a partially coiled tube which exits the abdominal cavity through theinguinal canal.
Etymology
[edit]Vas deferensisLatin,meaning "carrying-away vessel" whileductus deferens,also Latin, means "carrying-away duct".[1]
Structure
[edit]The human vas deferens measures 30–35 cm in length, and 2–3 mm in diameter.[2]: 1297 It is continuous proximally with the tail of the epididymis,[2]: 1296 and exhibits a tortuous, convoluted initial/proximal section (which measures 2–3 cm in length). Distally, it forms a dilated and tortuous segment termed theampulla of vas deferensbefore ending[2]: 1297 by uniting with aduct of the seminal vesicleto form theejaculatory duct.[3]Together they form part of thespermatic cord.[4]
Blood supply
[edit]The vasa deferentia are supplied with blood by accompanying arteries, the (arteries of vas deferens). These arteries normally arises from thesuperior(sometimesinferior)vesical arteries,a branch of theinternal iliac arteries.[5]
Innervation
[edit]The vas deferens receives innervation from an autonomic plexus of post-ganglionic sympathetic fibres derived from theinferior hypogastric plexus.[2]: 1297
It is innervated by a variety ofnerve endings,although of theefferent nervesthe sympathetic innveration dominates.[6]Adrenergic junctions(those which releasenoradrenaline) are found in thesmooth musclelayers.[7]Cholinergic synapsesandvasoactive intestinal peptide synapsesare found in theconnective tissueof themucosa.[8]
Anatomical relations
[edit]Within the spermatic cord, the vas deferens is situated posterior (and parallel to) the vessels of the spermatic cord.[2]: 1297
The vas deferens traverses the inguinal canal to reach thepelvic cavity;it enters the pelvic cavity lateral to theinferior epigastric vessels.At the deep inguinal ring, the vas deferens diverges from the testicular vessels to pass medially to reach the base of the prostate posteriorly.[2]: 1297
Histology
[edit]The vas deferens consists of an external adventitial sheath containing blood vessels and nerves, a muscular middle layer composed of three layers of smooth muscle (with a circular muscle layer interposed between two longitudinal muscle layers), and an internal mucosal lining consisting ofpseudostratifiedcolumnar epithelium (which bears the non-motilestereocilia).[2]: 1297 [9]
The vas deferens has the greatest muscle-to-lumen ratio of any hollow organ.[2]: 1297
Function
[edit]Duringejaculation,the smooth muscle in the walls of the vas deferens contracts reflexively, thus propelling the sperm forward. This is also known asperistalsis.[10]The sperm are transferred from each vas deferens into the urethra, partially mixing with secretions from the maleaccessory sex glandssuch as theseminal vesicles,prostate glandand thebulbourethral glands,which form the bulk ofsemen.[11]
Clinical significance
[edit]Contraception
[edit]Avasectomyis a method ofcontraceptionin which the vasa deferentia are permanently cut. In some cases, it can be reversed. A modern variation,vas-occlusive contraception,involves injecting an obstructive material into the ductus to block the flow of sperm.[12]
Disease
[edit]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 ofcystic fibrosis), causingmale infertility.Acquired obstructions can occur due to infections. To treat these causes of male infertility, sperm can be harvested bytesticular sperm extraction(TESE) or microsurgical epididymal sperm aspiration (MESA).[13]
Uses in pharmacology and physiology
[edit]The vas deferens has a dense sympathetic innervation,[14]making it a useful system for studying sympathetic nerve function and for studying drugs that modify neurotransmission.[6]
It has been used:
- as a bioassay for the discovery ofenkephalins,the endogenous opiates.[15]
- to demonstrate quantal transmission from sympathetic nerve terminals.[16]
- as the first direct measure of free Ca2+concentration in a postganglionic nerve terminal.[17]
- to develop an optical method for monitoring packeted transmission (similar toquantal transmission).[18]
Other animals
[edit]Most vertebrates have some form of duct to transfer the sperm from thetestesto theurethra.Incartilaginous fishandamphibians,sperm are carried through thearchinephric duct,which also partially helps to transport urine from the kidneys. Inteleosts,there is a distinct sperm duct, separate from theureters,and often called the vas deferens, although probably not trulyhomologouswith that in humans.[19]The vas deferens loops over the ureter inplacental mammals,but not inmarsupial mammals.[20][21]
In cartilaginous fishes, the part of the archinephric duct closest to the testis is coiled up to form anepididymis.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.[19]
Inamniotes,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.[19]
The only vertebrates to lack any structure resembling a vas deferens are the primitivejawless fishes,which release sperm directly into the body cavity, and then into the surrounding water through a simple opening in the body wall.[19]
Additional images
[edit]-
Male reproductive system. -
Coronal section of pelvis, showing arrangement of fasciae. 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 vesiculae 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
[edit]- Intra vas device
- Excretory duct of seminal gland
- Vas deferens in thereproductive system of gastropods
References
[edit]- ^Pozor, Malgorzata (2022). "Seminal Vesiculitis".Comparative Veterinary Anatomy:825–833.doi:10.1016/B978-0-323-91015-6.00067-4.ISBN9780323910156.S2CID245049526.
- ^abcdefghGray's anatomy: the anatomical basis of clinical practice.Susan Standring (Forty-second ed.). [New York]. 2021.ISBN978-0-7020-7707-4.OCLC1201341621.
{{cite book}}:CS1 maint: location missing publisher (link) CS1 maint: others (link) - ^Gonzales, GF (December 2001). "Function of seminal vesicles and their role on male fertility".Asian Journal of Andrology.3(4): 251–8.PMID11753468.
- ^Liu, Longfei (2019). "Chapter 1 - Applied Anatomy of the Scrotum and its Contents".Scrotoscopic Surgery.Academic Press.pp. 1–8.doi:10.1016/B978-0-12-815008-5.00001-7.ISBN978-0-12-815008-5.S2CID81721236.
- ^
One or more of the preceding sentences incorporates text in thepublic domainfrompage 615of the 20th edition ofGray's Anatomy(1918)
- ^abBurnstock, G; Verkhratsky, A (2010). "Vas deferens--a model used to establish sympathetic cotransmission".Trends in Pharmacological Sciences.31(3): 131–9.doi:10.1016/j.tips.2009.12.002.PMID20074819.
- ^Mirabella, Nicola; Squillacioti, Caterina; Varricchio, Ettore; Genovese, Angelo; Paino, Giuseppe (2003-05-01)."Innervation of vas deferens and accessory male genital glands in the water buffalo (Bubalus bubalis): Neurochemical characteristics and relationships to the reproductive activity".Theriogenology.59(9): 1999–2016.doi:10.1016/S0093-691X(02)01260-8.ISSN0093-691X.PMID12600736– viaElsevier.
- ^Alm, Per (1982-07-01)."On the autonomic innervation of the human vas deferens".Brain Research Bulletin.9(1–6).Elsevier:673–677.doi:10.1016/0361-9230(82)90172-1.ISSN0361-9230.PMID6184134.S2CID4761228.
- ^Höfer, D.; Drenckhahn, D. (May 1996)."Cytoskeletal differences between stereocilia of the human sperm passageway and microvilli/stereocilia in other locations".The Anatomical Record.245(1): 57–64.doi:10.1002/(SICI)1097-0185(199605)245:1<57::AID-AR10>3.0.CO;2-8.ISSN0003-276X.PMID8731041.S2CID7457415.
- ^Berridge, Michael J. (2008)."Smooth muscle cell calcium activation mechanisms".The Journal of Physiology.586(21): 5047–5061.doi:10.1113/jphysiol.2008.160440.PMC2652144.PMID18787034.
- ^Mann, T (1954).The Biochemistry of Semen.London: Methuen & Co; New York: John Wiley & Sons.RetrievedNovember 9,2013.
- ^Cook, Lynley A; Van Vliet, Huib AAM; Lopez, Laureen M; Pun, Asha; Gallo, Maria F (2014)."Vasectomy occlusion techniques for male sterilization".Cochrane Database of Systematic Reviews.2014(3): CD003991.doi:10.1002/14651858.CD003991.pub4.PMC7173716.PMID24683020.
- ^Schroeder-Printzen, I. (1 December 2000)."Microsurgical epididymal sperm aspiration: aspirate analysis and straws available after cryopreservation in patients with non-reconstructable obstructive azoospermia".Human Reproduction.15(12): 2531–2535.doi:10.1093/humrep/15.12.2531.PMID11098022.
- ^Sjöstrand, N.O. (1965)."The adrenergic innervation of the vas deferens and the accessory male genital organs".Acta Physiologica Scandinavica.257:S1–82.
- ^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.Bibcode:1975Natur.258..577H.doi:10.1038/258577a0.PMID1207728.S2CID95411.
- ^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.Bibcode:1987Natur.326..605B.doi:10.1038/326605a0.PMID2882426.S2CID4303337.
- ^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.doi:10.1111/j.1469-7793.1997.521bj.x.PMC1159525.PMID9279805.
- ^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.doi:10.1113/jphysiol.2002.019612.PMC2290369.PMID12068045.
- ^abcdRomer, Alfred Sherwood; Parsons, Thomas S. (1977).The Vertebrate Body.Philadelphia, PA: Holt-Saunders International. pp. 393–395.ISBN978-0-03-910284-5.
- ^C. Hugh Tyndale-Biscoe (2005).Life of Marsupials.Csiro Publishing.ISBN978-0-643-06257-3.
- ^Patricia J. Armati; Chris R. Dickman; Ian D. Hume (17 August 2006).Marsupials.Cambridge University Press.ISBN978-1-139-45742-2.
External links
[edit]
- Anatomy photo:36:07-0301at the SUNY Downstate Medical Center— "Inguinal Region, Scrotum and Testes: Layers of the Spermatic Cord"
- Anatomy photo:44:02-0301at the SUNY Downstate Medical Center— "The Male Pelvis: Distribution of the Peritoneum in the Male Pelvis"
- MedicalMnemonics.com:2424 319[dead link]
- Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna
- inguinalregionat The Anatomy Lesson by Wesley Norman (Georgetown University) (testes)
