Question

Describe what happens in an XX and XY individual from fetal life all the way to elderly age in terms of their reproductive physiology. Note commonalities and differences between XX and XY. Include sex differentiation, germ cell formation/maturation, hormones (origins and targets), and phenotypic changes.Include charts and/or flow diagrams

Answer 1

XX individual develops into females and the fetus which inherited XY chromosome will develop into male because of  gene called SRY in the sex-determining region of the short arm of the Y which lead to the synthesis of testosterone around 6th week of fetal development, a masculinizing hormone. It promotes the growth of male reproduction organs in the fetus. Those that do not have Y chromosome will begin to develop ovaries and other female sexual characters. Though the reproductive organs are present by birth, they keep mature until puberty. Androgen is initially thought as only male s@x hormones. Later, its presence is observed in females but at lower levels. Around third month of gestation, Müllerian inhibiting hormone secreted by sertoli cells leads to atrophy of Müllerian ducts and further development into fallopian tubes and uterus. S@x differentiation into males in zygote is stimulated by testosterone by the development of Wolffian ducts into the sp@rmatic ducts. External genital differentiation in fetus occurs between 8 and 12 weeks when androgen acts on phallus to enlarge and fusion of urogenital groove and sinus develops into unambiguous p@nis with a phallic urethra and scrotum. Visible secondary sexual characters in female at puberty is regulated by estradiol. Female reproduction hormones such as LH, FSH, progesterone along with estrogen play central role in ovualtion, menstruation and pregnancy.