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DEVELOPMENT OF OVARIES/UTERUS/UTERINE TUBES & DEVELOPMENTAL

ANOMALIESLecture by Prof. Dr. Ansari

(M.B;B.S. Semester II students only)

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The ovaries development

• Is from the same source as the testis develops.

• The intermediate mesoderm/ genital ridge, is invaded by the sex cells arising from the yolk sac endoderm.

• These sex cells are having XX chromosomal complement, in absence of SRY gene, the anti-mullerian factor is not produced.

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Genital ridge

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Migration of sex cellsAlong dorsal mesentery

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The sex cells multiply

• And increase in number, & spread into the genital ridge.

• The mullerian duct system develops parallel to the mesonephric duct.

• The primary sex cords grows into the medulla.

• They give rise to secondary sex cords.• Later they form the primordial ovarian

follicles.

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The paramesonephric ducts are formed by infolding of the coelomic epithelium.

• Parallel to the mesonephric ducts,

paramesonephric ducts grows/ Mullerian ducts.

• These will later form the fallopian tubes from the upper 1/3rd, fundus, body and cervix from the fused middle 1/3rd of the PMND, and lower 1/3rd will form the upper part of vagina.

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Paramesonephric duct

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The lower end of the PMND

• It opens up in the urogenital sinus/ the posterior wall of cloaca.

• The vagina develops from the sinovaginal bulb.

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Congenital anomalies of uterusdevelopment

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Unicornuate - Where one of the Müllerian duct fails to develop

resulting in a single uterine horn.

• Bicornuate - Both ducts form but one duct develops to a greater extent than the other.

• Consequently a small "rudimentary horn" exists, which may end blind or be continuous with the dominant horn.

• There is usually only one cervix.

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Double vaginas

• Double - Complete failure of fusion of the Müllerian ducts. As a result of the independence of the ducts, two uteri develop, each with their own cervix. In addition one or two vaginas may be found.

• Septate - Both ducts develop but they only partially fuse. This leaves a septum at the fundus

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External genitalia development

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The female external genitaliadevelopment

• At the lower end of the embryo, around the cloacal membrane a median genital tubercle grows and it is called as phallus.

• On either side of the cloacal membrane, a labioscrotal swellings develop, the fore runner of the labia majora.

• In female fetus, the labioscrotal swelling will give rise to labia majora.

• The labia minora is developing from the urethral folds that has not united.

• The undeveloped phallus remains as clitoris.

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The embryological derivatives• Clitoris = median genital

tubercle

• Labia majora = Labioscrotal swellings/lateral genital swellings

• Labia minora = Urethral groove• Vagina = sinovaginal bulb

• Uterus/tubes = Paramesonephric ducts

• Ovary = Genital ridge/Intermediate mesoderm

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Imperforate hymen

• If the cloacal membrane does not rupture

• It will give rise to imperforate hymen

• A congenital anomaly