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Male genital system 23.3.2009 Gonads, genital ducts, accesory glands, external genitalia Developmental relations in between urinary system and genital systém (urogenital system) • Pronephros (non-functional) • Mesonephros (embryonal kidney) and ductus mesonephridicus (Wolff) • Metanephros (permanent kidney) • Urinary systém develops from 4th week • Genital systém develops from 5th week Mesonephros degenerate at the end of the first trimester, but some components persist • Mesonephric tubules – ductulí efferentes testis • Ductus mesonephridicus (Wolffian duct) • ductus epididymidis • ductus deferens • ductus ejaculatorius, • vesiculae seminales Origin of male genital system • material – intermediate mesoderm • mesoderm – genital ridge – during embryo folding become ventrally localised • coelomic epithelium is in the surface proliferates – primitive sex cords • primordial germ cells • onset of gonad development is indifferent • until 7th week structure of gonad is identical in both sex Development of male phenotype of gonad testes • TDF faktor (SRY gen) on short arm of Y chromosome) • Y chromosome determines medulla of gonad– primitive sex cords – proliferation into medulla - medullary cords – seminiferous tubulus and rete testes • Sertoli cells – production of anti-mullerian hormon (AMH) • mesenchymal cells – interstitial cells of Leydig – testosterone – diferentiation of mesonephric ducts and external genitalia Development of genital system • Both sex have two pairs of ducts • D.mesonephricus, Wolffi • D.paramesonephricus, Mulleri Male – Wolffian duct differentiation – testosterone (regulates by hCG of placenta, later by fetal gonadotropin) from 8th week • + Sertoli cells – antimullerian substance (MIS) degeneration of Mullerian duct Indiferent stage of external genitalia Development of external genitalia 3 structures for both sex Until the 12th week are genitalia of both sex similar. • Genital tubercle-> phallus • Urogenital folds -> urethral groove, of endodermal origin, forms urethral plate -> penile urethra • From the glans of penis (ectoderm) glandular plate– terminaln part of urethr • Scrotal swellings -> scrotum Diferentiation of external genitalia and accessory genital glands - dihydrotestosteron • during fetal period , from the 9th week , testosterone converted to dihydrotestosteron • diferentiation – penis, scrotum • + prostate, bulbourethral glands • from endoderm of urethra, evagination (induced by adjacent mesenchyme, under dihydrotestosterone control) Indiferentn stages of external genitalia Testes • Seminiferous tubules • Tubuli recti , rete testis Spermatogenic epithelium, spermatogenesis Spermiogenesis • • • • formation of the acrosome condensation of the nucleus formation of neck, middle piece and tail shedding of the most of the cytoplasm Spermiogenesis Prostate
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