Seminal vesicles

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Seminal vesicle
urinary tract and male reproductive system, with the seminal vesicles seen top right
The seminal vesicles seen near the prostate, viewed from in front and above.
Details
PrecursorWolffian duct
SystemMale reproductive system
ArteryInferior vesical artery, middle rectal artery
LymphExternal iliac lymph nodes, internal iliac lymph nodes
Identifiers
Latinvesiculae seminales, glandulae vesiculosae
MeSHD012669
TA98A09.3.06.001
TA23631
FMA19386
Anatomical terminology]

The seminal vesicles (also called vesicular glands

urinary bladder of male mammals. They secrete fluid that partly composes the semen
.

The vesicles are 5–10 cm in size, 3–5 cm in diameter, and are located between the

cuboidal
cells. The vesicles are present in many groups of mammals, but not marsupials, monotremes or carnivores.

Inflammation of the seminal vesicles is called seminal vesiculitis and most often is due to bacterial infection as a result of a

blood in the semen
. It is usually treated with antibiotics, although may require surgical drainage in complicated cases. Other conditions may affect the vesicles, including congenital abnormalities such as failure or incomplete formation, and, uncommonly, tumours.

The seminal vesicles have been described as early as the second century AD by Galen, although the vesicles only received their name much later, as they were initially described using the term from which the word prostate is derived.

Structure

The seminal vesicles are a pair of glands in males that are positioned below the

vasa deferentia, where they enter the prostate. Each vesicle is a coiled and folded tube, with occasional outpouchings termed diverticula in its wall.[2] The lower part of the tube ends as a straight tube called the excretory duct, which joins with the vas deferens of that side of the body to form an ejaculatory duct. The ejaculatory ducts pass through the prostate gland before opening separately into the verumontanum of the prostatic urethra.[2] The vesicles are between 5–10 cm in size, 3–5 cm in diameter, and have a volume of around 13 mL.[3]

The vesicles receive blood supply from the vesiculodeferential artery, and also from the

Lymphatic drainage occurs along the venous routes, draining into the internal iliac nodes.[3]

The vesicles lie behind the bladder at the end of the vasa deferentia. They lie in the space between the bladder and the rectum; the bladder and prostate lie in front, the tip of the ureter as it enters the bladder above, and Denonvilliers' fascia and the rectum behind.[3]

Development

Further information: Development of the urinary system

In the developing

reproductive tracts of the male and female respectively.[4]

In the male, under the influence of

ductus deferens and, via a small outpouching near the developing prostate, the seminal vesicles.[4] Sertoli cells secrete anti-Müllerian hormone, which causes the paramesonephric duct to regress.[4]

The development and maintenance of the seminal vesicles, as well as their secretion and size/weight, are highly dependent on

luteinizing hormone receptors, and hence may also be regulated by the ligand of this receptor, luteinizing hormone.[6]

Microanatomy

The inner lining of the seminal vesicles (the

cube-shaped cells.[7] There are varying descriptions of the lining as being pseudostratified and consisting of column-shaped cells only.[8] When viewed under a microscope, the cells are seen to have large bubbles in their interior. This is because their interior, called cytoplasm, contains lipid droplets involved in secretion during ejaculation.[7] The tissue of the seminal vesicles is full of glands, spaced irregularly.[7] As well as glands, the seminal vesicles contain smooth muscle and connective tissue.[7] This fibrous and muscular tissue surrounds the glands, helping to expel their contents.[3] The outer surface of the glands is covered in peritoneum.[3]

  • Low magnification micrograph of seminal vesicle. H&E stain.
    Low magnification micrograph of seminal vesicle. H&E stain.
  • High magnification micrograph of seminal vesicle. H&E stain.
    High magnification micrograph of seminal vesicle. H&E stain.

Function

The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes

ejaculated during a male sexual response.[8]

About 70-85% of the seminal fluid in humans originates from the seminal vesicles.[10] The fluid consists of nutrients including fructose and citric acid, prostaglandins, and fibrinogen.[9] Fructose is not produced anywhere else in the body except in the seminal vesicles. It provides a forensic test in rape cases.

Nutrients help support

female reproductive tract such as the fallopian tubes, to ensure that sperm are less likely to be expelled.[9]

Clinical significance

Disease

Diseases of the seminal vesicles as opposed to that of prostate gland are extremely rare and are infrequently reported in the medical literature.[11]

Congenital anomalies associated with the seminal vesicles include failure to develop, either completely (agenesis) or partially (hypoplasia), and cysts.[12][13] Failure of the vesicles to form is often associated with absent vas deferens, or an abnormal connection between the vas deferens and the ureter.[3] The seminal vesicles may also be affected by cysts, amyloidosis, and stones.[12][13] Stones or cysts that become infected, or obstruct the vas deferens or seminal vesicles, may require surgical intervention.[8]

Seminal vesiculitis (also known as spermatocystitis) is an inflammation of the seminal vesicles, most often caused by bacterial infection.

hydatid disease.[12][13] These diseases are investigated, diagnosed and treated according to the underlying disease.[8]

Benign tumours of the seminal vesicles are rare.

squamous cell carcinoma, yolk sac tumor, neuroendocrine carcinoma, paraganglioma, epithelial stromal tumors and lymphoma.[18]

Investigations

Symptoms due to diseases of the seminal vesicles may be vague and not able to be specifically attributable to the vesicles themselves; additionally, some conditions such as tumours or cysts may not cause any symptoms at all.[8] When diseases is suspected, such as due to pain on ejaculation, blood in the urine, infertility, due to urinary tract obstruction, further investigations may be conducted.[8]

A

digital rectal examination, which involves a finger inserted by a medical practitioner through the anus, may cause greater than usual tenderness of the prostate gland, or may reveal a large seminal vesicle.[8]
Palpation is dependent on the length of index finger as seminal vesicles are located above the prostate gland and retrovesical (behind the bladder).

A urine specimen may be collected, and is likely to demonstrate blood within the urine.[8] Laboratory examination of seminal vesicle fluid requires a semen sample, e.g. for semen culture or semen analysis. Fructose levels provide a measure of seminal vesicle function and, if absent, bilateral agenesis or obstruction is suspected.[12]

Imaging of the vesicles is provided by

transrectal ultrasound, CT or MRI scans.[8] An examination using cystoscopy, where a flexible tube is inserted in the urethra, may show disease of the vesicles because of changes in the normal appearance of the nearby bladder trigone, or prostatic urethra.[8]

Other animals

The evolution of seminal vesicles may have been influenced by sexual selection. They occur in many groups of mammals,[19] but are absent in marsupials,[20] monotremes, and carnivorans.[21][22] The function is similar in all mammals they are present in, which is to secrete a fluid as part of semen that is ejaculated during the sexual response.[19]

History

The action of the seminal vesicles has been described as early the second century AD by Galen, as "glandular bodies" that secrete substances alongside semen during reproduction.[21] By the time of Herophilus the presence of the glands and associated ducts had been described.[21] Around the time of the early 17th century the word used to describe the vesicles, parastatai, eventually and unambiguously was used to refer to the prostate gland, rather than the vesicles.[21] The first time the prostate was portrayed in an individual drawing was by Reiner De Graaf in 1678.[21]

The first described use of laparoscopic surgery on the vesicles was described in 1993; this is now the preferred approach because of decreased pain, complications, and a shorter hospital stay.[8]

Additional images

  • Seminal vesicles seen on an MRI scan through the pelvis. The large cyan-coloured area is the bladder, and the lobulated smaller structures below it are the vesicles.
    Seminal vesicles seen on an MRI scan through the pelvis. The large cyan-coloured area is the bladder, and the lobulated smaller structures below it are the vesicles.
  • Seminal vesicles seen in a cadaveric specimen from on top, with the bladder to the bottom of the image, and the rectum at the top. Their position near the vas deferentia can be seen.
    Seminal vesicles seen in a cadaveric specimen from on top, with the bladder to the bottom of the image, and the rectum at the top. Their position near the vas deferentia can be seen.
  • Fundus of the bladder with the vesiculae seminales.
    Fundus of the bladder with the vesiculae seminales.

See also

References

  1. ISBN 978-0-8138-1394-3
    .
  2. ^
    ISBN 978-0781772006
    .
  3. ^
    OCLC 920806541.{{cite book}}: CS1 maint: location missing publisher (link
    )
  4. ^
    ISBN 9781496383907
    .
  5. ISBN 978-3-642-46018-0
    .
  6. ^
    PMID 11753468
    .
  7. ^
    ISBN 9780702047473
    .
  8. ^
    ISBN 9781119245193. {{cite book}}: |last1= has generic name (help)CS1 maint: multiple names: authors list (link
    )
  9. ^
    ISBN 978-1-4557-7016-8
    .
  10. ISBN 978-0323078429
    .
  11. ^ Dagur G, Warren K, Suh Y, Singh N, Khan SA. Detecting diseases of neglected seminal vesicles using imaging modalities: A review of current literature. Int J Reprod Biomed. 2016;14(5):293-302.
  12. ^
    ISBN 978-1550093650
    .
  13. ^ a b c "Seminal vesicle diseases". Geneva Foundation for Medical Education and Research. Archived from the original on 2014-04-26.
  14. ^ "Is seminal vesiculitis a discrete disease entity? Clinical and microbiological study of seminal vesiculitis in patients with acute epididymitis". 4 July 2023.
  15. ISBN 9781901865042
    .
  16. PMID 21696400
    .
  17. PMID 24391141
    .
  18. ^
    PMID 27072175
    .
  19. ^
    ISBN 9781260092042
    .
  20. ISBN 978-0-521-33792-2
    .
  21. ^
    S2CID 44922919
    . The humor produced in those glandular bodies is poured into the urinary passage in the male along with semen and its uses are to excite to the sexual act, to make coitus pleasurable, and to moisten the urinary passageway.
  22. ^ Dixson, Alan F. "Sexual selection and evolution of the seminal vesicles in primates." Folia Primatologica 69.5 (1998): 300-306.

External links

Wikimedia Commons has media related to Seminal vesicles.
  • Histology image: 17501loa – Histology Learning System at Boston University - "Male Reproductive System: prostate, seminal vesicle"
  • Anatomy photo:44:04-0202 at the SUNY Downstate Medical Center - "The Male Pelvis: The Urinary Bladder"
  • Anatomy photo:44:08-0103 at the SUNY Downstate Medical Center - "The Male Pelvis: Structures Located Posterior to the Urinary Bladder"
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