INDS 211 Lecture Notes - Lecture 28: Karyotype, Sexual Differentiation, Sex Steroid

• School: McGill University
• Department: Interndisciplinary Studies
• Course: INDS 211
• Professor: Bill Buckett

Document Summary

Formation of internal genitalia: before the embryonic to fetal transition, the gonads and reproductive ducts of the urogenital ridge are bipotential. In the absence of sry, ovaries differentiate, wolffian ducts degenerate, and m llerian ducts develop into a simple columnar epithelial tube that will differentiate into the oviducts, uterus, cervix, and upper portion of the vagina. Disorders of sex development (dsd: def: "condition showing disagreement b/wxm, gonadal and phenotypic sex, term proposed to replace: Intersex, hermaphroditism, pseudohemaphroditism, sex reversal: ambigous genitalia (note that all dsds have ambiguity, alternatively: can call them variations of sex development or differences in sex development instead of disorders of sex development. Examples of sex chromosome dsd classifications: klinefelter"s + variants; 47, xxy; turner"s + variants: 45 x; Mixed gonadal dysgenesis: 45x, 46 xy: chimerism: 46 xx/ 46 xy, eg. 46,xx testicular dsd (xx male) (note: xx, sry negative: normal female) 1: xx, sry positive: male phenotype because of translocation of sry gene onto x chromosome.