BIO380H5 Lecture Notes - Lecture 26: Intermediate Mesoderm, Mesentery, Development Of The Gonads
Document Summary
Bio 380 lecture 26 genital system. The urogenital system is derived from the intermediate mesoderm. Early in development, but sexes look the same because the embryo is at an indeterminate stage; there is no phenotypic differentiation. The sex organs such as the ovaries, testis, epididymis etc are derived from the intermediate mesoderm. After fertilization, you cannot change gender: genetic determination of gender occurs at fertilization, woman have an extra inactivate x chromosome which condenses as a batt body. At the 7th week of development, phenotypic characteristics such as the testis or ovaries are apparent. Gonads must be ready to receive pgc. The female genotype is the default, before sry gene is expressed in male. Sry genes comes from the pgc and the gonadal tissues. It is expressed at the time of fertilization. It is found in the male gonads: tdf is dependent on the expression of the sry gene.
