Seminal Vesicle

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seminal vesicle

[′sem·ən·əl ′ves·i·kəl]
(anatomy)
A saclike, glandular diverticulum on each ductus deferens in male vertebrates; it is united with the excretory duct and serves for temporary storage of semen.

Seminal Vesicle

 

in male salientians and birds and in some male fish and mammals (including man), a glandular widening or protrusion of the terminal portion of the seminal duct that releases an alkaline mucosal secretion needed to nourish and mobilize spermatozoa. In most animals the secretion of the seminal vesicles is a component of semen that serves to liquefy sperm and, in some animals, promotes the formation of sper-matophores from sperm.

Seminal vesicles are paired or unpaired. They are formed during embryonic development from various portions of the deferent ducts and may be simple widenings or sacculated processes of the ducts. In some animals seminal vesicles are independent structures united to the deferent ducts only by a narrow canal. Seminal vesicles are especially developed in some rodents and insectivores; they are absent in monotremes, marsupials and many predatory animals.

In man, the seminal vesicles form a paired organ 4–5 cm long, 2 cm wide, and 1.0–1.5 cm thick. They are located in connective tissue between the posteroinferior surface of the urinary bladder and the rectum, adjacent to the base of the prostate. The vesicles are convoluted tubes with numerous recesses. The vesicular wall consists of an external connective-tissue membrane, a weakly developed muscular membrane, a submucosal layer, and a mucous membrane with columnar or cubical epithelium. The excretory duct of the seminal vesicles is connected to the terminal portion of the seminal canal, forming the ejaculatory duct.

References in periodicals archive ?
Computerized tomography (CT) images showed a 6 cm heterogeneous, infiltrative tumor within the prostate gland extending to the trigon of the bladder, left seminal vesicle and rectum (Figure 1).
Intravenous urography may show a smooth indentation on the urinary bladder from mass effect of the enlarged seminal vesicle.
In Hymenoptera, the sperm may be free in the seminal vesicle, as reported for parasitic wasps (Lino-Neto et al.
Technical aspects of RP in locally advanced prostate cancer: RP in locally advanced prostate cancer requires special expertise and includes removal of whole prostate gland en-bloc (b/w urethra and bladder) with good apical dissection, wide resection of neuro-vascular (NV) bundle and complete resection of both seminal vesicles.
The secretions by the prostate also influence the sperm and seminal vesicles.
SVI was included in the present examination as BPH is commonly regarded as closely associated with elevated levels of androgens-as described above-with the seminal vesicles being one of the most typical target organs of these hormones.
The seminal vesicles were removed before determining the volume of the prostate (by water displacement).
Thomson AA1, Marker PC (2006) Branching morphogenesis in the prostate gland and seminal vesicles.
Simultaneously the prostate gland (walnut-sized gland located between the bladder and the penis, just in front of the rectum) and seminal vesicles (pair of pouch-like glands behind the bladder) release secretions to make seminal fluid.
Similarly treated male mice develop testicular cancer and abnormalities of the prostate and seminal vesicles (SVs) (McLachlan 1977; McLachlan and Dixon 1977).