Urogenital Sinus

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Related to Urogenital Sinus: Urogenital folds

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Urogenital Sinus

the cavity into which the efferent ducts of the reproductive and excretory systems empty in many vertebrates. The urogenital sinus opens into the cloaca in elasmobranchs and holocephalans, in chelonians, and in monotremes; in vertebrates that have a reduced cloaca—polypterids, chondrosteans, and holosteans, males of lower teleosts, and viviparous mammals—the urogenital sinus opens directly to the outside.

The urogenital sinus in the mammalian embryo develops from the lower ventral section of the cloaca; the gonaducts and urinary bladder open into this section, as do the ureters of monotremes. In female eutherians (placental mammals) and in women, the urogenital sinus is greatly shortened, forming the vestibule of the vagina. The vestibule is inferior to and separated from the vagina in ungulates, rodents, prosimians, anthropoid apes, and women by a membranous structure called the hymen. In males of viviparous mammals and in men, the upper portion of the urethra develops from the urogenital sinus.

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References in periodicals archive ?

The hymenal membrane separates the vaginal lumen from the urogenital sinus. Secondary to degeneration of the central epithelial cells, the hymen typically ruptures, leaving a thin fold of mucous membrane around the vaginal introitus.

The genesis of vaginal anomalies

An elective Caesarean section was performed and the newborn was treated early, the surgical act consisting of an excision of the cystic accessory phallic urethra with urogenital sinus septation and vaginoplasty.

Urethral Duplication with a Cystic Phallic Urethra Associated with a Uterus Didelphys, Partial Agenesis of the Tibia, and an Equinovarus Foot

These two cases, similar to the present cases, exhibited a severe phenotype with clitoromegaly, labial fusion, and/or single urogenital sinus at birth.

A Novel Null Mutation in P450 Aromatase Gene (CYP19A1) Associated with Development of Hypoplastic Ovaries in Humans

The formation of a urogenital sinus in these animals occurs due absence of an external vaginal ostium (Yalcinkaya et al., 1993; Browne et al., 2006; Glickman et al., 2006).

Intrauterine Development of Female Genital Organs in Cavia porcellus (Rodentia: Caviidae)

The complexity of the folds increases towards the urogenital sinus with the formation of branched villi whose epithelium flattens (Fig.

The Female Reproductive System of Zearaja chilensis (Guichenot, 1848) (Chondrichthyes, Rajidae). Gametogenesis and Microscopic Validation of Maturity Criteria/ El Sistema Reproductor Femenino de Zearaja chilensis (Guichenot, 1848) (Chondrichthyes, Rajidae). Gametogenesis y Validacion Microscopica de los Criterios de Madurez

Affected females are born with enlarged clitoris, fused labioscrotal folds and a urogenital sinus which may become a phallic urethera.

Classic congenital adrenal hyperplasia: A delayed presentation

The 18-day-old pig embryo has a well-defined genital tubercle (Figure 4-3), a swelling on the ventral surface between the umbilical cord and opening of the urogenital sinus. This will eventually form the male or female external genitalia.

Chapter 4: Sexual differentiation

"Embryologically, the vulva, distal vagina, trigone, and urethra are all derived from the urogenital sinus and contain the highest concentration of estrogen receptors.

Genital atrophy common after stopping HT: the dyspareunia many women experience has more to do with introital stenosis than vaginal dryness

The Sonic hedgehog (Shh) gene is expressed in the epithelium of the male urogenital sinus and is not regulated by testosterone.

Hypospadias and endocrine disruption: is there a connection? (Children's Health Review)

The origin of SCEVs has been proposed to be from a possible embryonic remnant.[1] Although the embryologic development of the vagina is controversial, the hymenal ring appears to be derived from the urogenital sinus.[1,17,18] The greatest controversy exists on the relative contributions of the mullerian ducts and urogenital sinus to the development of the vagina.

Spindle Cell Epithelioma of the Vagina Shows Immunohistochemical Staining Supporting Its Origin From a Primitive/Progenitor Cell Population

The other two theories are that it is a mild anomaly of a midline abdominal wall closure defect, or that it is a congenital fistula of the primitive urogenital sinus (3,4).

Successful Surgical Management of Congenital Prepubic Sinus

The cause of hypospadias is not known, it is presumed that affected foetus may secret inadequate quantities of testosterone or that there may be inadequate conversion of testosterone to dihydrotestosterone in target tissues of urogenital sinus and external genitalia.