| Seminal vesicle |
Human Male Anatomy
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Prostate with seminal vesicles and seminal ducts, viewed from in front and above.
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| Latin |
Vesiculae seminales |
| Gray's |
p.1246 |
| Artery |
Inferior vesical artery, middle rectal artery |
| Lymph |
External iliac lymph nodes, internal iliac lymph nodes |
| Precursor |
Wolffian duct |
| MeSH |
Seminal+Vesicles |
The seminal vesicles (Latin: glandulae vesiculosae) or vesicular glands [1] are a pair of simple tubular glands posteroinferior to the urinary bladder of some male mammals. Carnivores, marsupials, monotremes, and cetaceans do not have seminal vesicles.[2] Seminal vesicles are located within the pelvis.
Contents
- 1 Structure
- 1.1 Development
- 1.2 Histology
- 2 Function
- 3 Additional images
- 4 References
- 5 External links
Structure
The seminal vesicles are a pair of glands that are positioned below the bladder and lateral to the ductus deferens. The seminal vesicles are arranged as a series of glands which drain into a central duct. The duct unites with the ductus deferens to form the ejaculatory duct. [3]
The excretory duct of each seminal gland opens into the vas deferens as it enters the prostate gland.
Each seminal vesicle spans approximately 5 cm, though its full unfolded length is approximately 10 cm, but it is curled up inside the gland's structure.
Development
Each vesicle forms as an outpocketing of the wall of the ampulla of one vas deferens. The seminal vesicles develop as one of three structures of the male reproductive system that develops at the junction between the urethra and vas deferens. Both the urethra and vas deferens are derived from the mesonephric ducts, structures that develop from mesoderm. [4]
Histology
Under microscopy, the seminal vesicles can be seen to have a mucosa, consisting of a lining of interspersed columnar cells and a laminar propria; and a thick muscular wall. The lumen of the glands is highly irregular and stores secretions from the glands of the vesicles. In detail: [5]
- The epithelia is stratified columnar in character, similar to other tissues in the male reproductive system.
The height of these columnar cells, and therefore activity, is dependent upon testosterone levels in the blood.[citation needed]
- The lamina propria, containing underlying small blood vessels and lymphatics. Together with the epithelia, this is called the mucosa, and is arranged into convoluted folds, increasing the overall surface area
- A muscular layer, consisting of an inner circular and outer longitudinal layer of smooth muscle, can also be found.
Spermatazoa may occasionally be found within the lumen of the glands, even though the vesicles are blind-ended in nature. This is thought to be because of slight reflux due to muscular contractions of the urethera during ejaculation. [5]
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Low magnification micrograph of seminal vesicle. H&E stain.
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High magnification micrograph of seminal vesicle. H&E stain.
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Function
The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes semen. Lipofuscin granules from dead epithelial cells give the secretion its yellowish color. About 50-70%[6] of the seminal fluid in humans originates from the seminal vesicles, but is not expelled in the first ejaculate fractions which are dominated by spermatozoa and zinc-rich prostatic fluid. The excretory duct of each seminal gland opens into the corresponding vas deferens as it enters the prostate gland. Seminal vesicle fluid is alkaline, resulting in human semen having a mildly alkaline pH.[7] The alkalinity of semen helps neutralize the acidity of the vaginal tract[citation needed], prolonging the lifespan of sperm. Acidic ejaculate (pH <7.2) may be associated with Ejaculatory duct obstruction. The vesicle produces a substance that causes the semen to become sticky/jelly-like after ejaculation.
The thick secretions from the seminal vesicles contain proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine and prostaglandins. The high fructose concentrations provide nutrient energy for the spermatozoa when stored in semen in the laboratory.
In vitro studies have shown that sperm expelled together with seminal vesicular fluid show poor motility and survival, and the sperm chromatin is less protected. Therefore the exact physiological importance of seminal vesicular fluid is not clear.
Additional images
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Human male reproductive system.
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Coronal section of pelvis, showing arrangement of fasciae. Viewed from behind.
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Male pelvic organs seen from right side.
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Fundus of the bladder with the vesiculae seminales.
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Vesiculae seminales and ampullae of ductus deferentes, seen from the front.
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Vertical section of bladder, penis, and urethra.
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Cross section of seminal vesicle through a microscope.
References
- ^ Wilke; W. Lee Wilke, Rowen D. Frandson, Anna Dee Fails (2009). Anatomy and Physiology of Farm Animals. John Wiley and Sons. ISBN 0-8138-1394-8. Retrieved 2013-11-03.
- ^ http://urology.jhu.edu/newsletter/prostate_cancer511.php
- ^ Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell ; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. pp. 407–409. ISBN 978-0-8089-2306-0.
- ^ Larsen's human embryology (4th ed., Thoroughly rev. and updated. ed.). Philadelphia: Churchill Livingstone/Elsevier. 2009. pp. "Development of the urogenital system". ISBN 9780443068119.
- ^ a b Deakin, Barbara Young ... [et al.] ; drawings by Philip J. (2006). Wheater's functional histology : a text and colour atlas (5th ed. ed.). [Edinburgh?]: Churchill Livingstone/Elsevier. p. 355. ISBN 978-0-443-06850-8.
- ^ Kierszenbaum, Abraham L. (2002). Histology and cell biology : an introduction to pathology. St. Louis [u.a.]: Mosby. p. 558. ISBN 0-323-01639-1.
- ^ "CHEMICAL COMPOSITION OF HUMAN SEMEN AND OF THE SECRETIONS OF THE PROSTATE AND SEMINAL VESICLES". http://ajplegacy.physiology.org. Retrieved 2010-08-10.
External links
- BU Histology Learning System: 17501loa - "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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Systems and organs of the animal anatomy
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| Respiratory system |
- Bronchus
- Trachea
- Lung
- Diaphragm
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| Excretory system |
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| Nervous system |
Brain
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| Immune system |
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| Digestive system |
- Anus
- Colon
- Mouth
- Pancreas
- Rectum
- Small intestine
- Spleen
- Stomach
- Tongue
- Tooth
- Vermiform appendix
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| Other organs |
- Bone
- Ear
- Eye
- Head
- Heart
- Larynx
- Liver
- Nose
- Penis
- Pharynx
- Rhinarium
- Skeleton
- Skin
- Skull
- Tonsil
- Thymus
- Thyroid
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| Tissues |
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Male reproductive system (TA A09.3–4, TH H3.07.02, GA 11.1236)
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| Internal |
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Seminal
tract
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Testes
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- layers
- Tunica vaginalis
- Tunica albuginea
- Tunica vasculosa
- Appendix
- Mediastinum
- Lobules
- Septa
- Leydig cell
- Sertoli cell
- Blood-testis barrier
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Spermatogenesis
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- Spermatogonium
- Spermatocytogenesis
- Spermatocyte
- Spermatidogenesis
- Spermatid
- Spermiogenesis
- Spermatozoon
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Other
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- Seminiferous tubules
- Tubuli seminiferi recti
- Rete testis
- Efferent ducts
- Epididymis
- Paradidymis
- Spermatic cord
- Vas deferens
- Ejaculatory duct
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Accessory
glands
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- Seminal vesicles
- Excretory duct of seminal gland
- Prostate
- Urethral crest/Seminal colliculus/Prostatic utricle/Ejaculatory duct
- Prostatic sinus/Prostatic ducts
- Bulbourethral glands
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| External |
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Penis
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- root
- Crus
- Bulb
- Fundiform ligament
- Suspensory ligament
- body
- Corpus cavernosum
- Corpus spongiosum
- glans
- fascia
- superficial/subcutaneous
- deep/Buck's
- Tunica albuginea
- Septum of the penis
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Urinary
tract
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- Internal urethral orifice
- Urethra
- Prostatic
- Intermediate
- Spongy
- Navicular fossa
- External urethral orifice
- Lacunae of Morgagni
- Urethral gland
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Scrotum
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- layers
- skin
- Dartos
- External spermatic fascia
- Cremaster/Cremasteric fascia
- Internal spermatic fascia
- Perineal raphe
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noco/cong/tumr, sysi/epon
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Human systems and organs
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TA 2–4:
MS |
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Skeletal system
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- Bone
- Carpus
- Collar bone (clavicle)
- Thigh bone (femur)
- Fibula
- Humerus
- Mandible
- Metacarpus
- Metatarsus
- Ossicles
- Patella
- Phalanges
- Radius
- Skull (cranium)
- Tarsus
- Tibia
- Ulna
- Rib
- Vertebra
- Pelvis
- Sternum
- Cartilage
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Joints
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- Fibrous joint
- Cartilaginous joint
- Synovial joint
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Muscular system
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TA 5–11:
splanchnic/
viscus |
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mostly
Thoracic
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mostly
Abdominopelvic
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Digestive system+
adnexa
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- Mouth
- upper GI
- Oropharynx
- Laryngopharynx
- Esophagus
- Stomach
- lower GI
- Small intestine
- Appendix
- Colon
- Rectum
- Anus
- accessory
- Liver
- Biliary tract
- Pancreas
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GU: Urinary system
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- Kidney
- Ureter
- Bladder
- Urethra
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GU: Reproductive system
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- Female
- Uterus
- Vagina
- Vulva
- Ovary
- Placenta
- Male
- Scrotum
- Penis
- Prostate
- Testicle
- Seminal vesicle
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Endocrine system
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- Pituitary
- Pineal
- Thyroid
- Parathyroid
- Adrenal
- Islets of Langerhans
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| TA 12–16 |
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Circulatory system
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Cardiovascular system
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- peripheral
- Artery
- Vein
- Lymphatic vessel
- Heart
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Lymphatic system
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- primary
- secondary
- CNS equivalent
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Nervous system
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Integumentary system
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- Skin
- Subcutaneous tissue
- Breast
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Blood
(Non-TA) |
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General anatomy: systems and organs, regional anatomy, planes and lines, superficial axial anatomy, superficial anatomy of limbs
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