BIOL 129 Lecture Notes - Lecture 18: Sexual Differentiation, Prenatal Development, Spermatozoon
Document Summary
Fertilization: sperm and egg chromosomes combine to form a zygote (a single cell that will become the entire embryo) All eggs are x, sperm are either x or y. During development, sexual differentiation begins around 8 weeks. Due to differences in the levels of specific hormones in the male and female embryo. Any changes to sex hormone levels can affect sexual development. Three important structures: (1) gonadal ridge: becomes testes or ovaries (2) wolffian duct (3) mullerian duct. Testes produce two male sex hormones that trigger this change. Mullerian ducts becomes fallopian tubes, uterus, and upper vagina. Occurs as long as male hormones are not produced. 5 weeks: male and female embryos look the same. Intersex: general term used for a variety of conditions in which a person is born with a reproductive a(cid:374)ato(cid:373)(cid:455) that does(cid:374)"t fit the t(cid:455)pi(cid:272)al defi(cid:374)itio(cid:374)s of fe(cid:373)ale or (cid:373)ale. Ge(cid:374)eti(cid:272) (cid:272)o(cid:374)ditio(cid:374): (cid:271)od(cid:455)"s (cid:272)ells (cid:272)a(cid:374)(cid:374)ot respo(cid:374)d to testostero(cid:374)e.
