Thursday, April 20, 2023 1
DEVELOPMENT OF OVARIES/UTERUS/UTERINE TUBES & DEVELOPMENTAL
ANOMALIESLecture by Prof. Dr. Ansari
(M.B;B.S. Semester II students only)
Thursday, April 20, 2023 2
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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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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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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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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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