What determines the length of the menstrual cycle? Why is the luteal phase almost constant? Why is the follicular phase variable? What is the role of inhibin B? Explain positive feedback of estrogen. Why does basal body temperature rise after ovulation? Is LH surge alone sufficient? What is follicular atresia? Which cells synthesize estrogen? Histological changes during proliferative phase. Histological changes during secretory phase. Why is secretory endometrium suitable for implantation? Physiology behind dysmenorrhea. Why do oral contraceptive pills prevent ovulation? Why is progesterone measured to confirm ovulation? PCOS Why does menopause increase osteoporosis? Differentiate spermatogenesis, spermiogenesis and spermiation. Why does spermatogenesis take about 74 days? Why does sperm production continue throughout life? Which stage undergoes meiosis I? Which stage undergoes meiosis II? Which stage is most radiosensitive? Why are Sertoli cells called nurse cells? Explain blood-testis barrier. Why are sperm protected from immune attack? Role of inhibin B. Capacitation. Acrosome reaction. Hyperactivation. Why can't freshly ejaculated sperm fertilize? Cryptorchidism. Effect of fever on spermatogenesis. Effect of anabolic steroids. Oligospermia causes. Azoospermia causes. Clinical use of finasteride. Why do males need estrogen? Why is anti-Müllerian hormone (AMH) considered the best marker of ovarian reserve? Why does obesity affect fertility? Explain reproductive aging. Hypogonadotropic hypogonadism. Hypergonadotropic hypogonadism. Role of inhibin and activin Why is pregnancy test based on hCG? Why does testosterone not suppress spermatogenesis despite negative feedback? kisspeptin give answers for given questions