we say that oestrogen and progesterone are secreated by ovaries but specifically by which parts of ovary?
The part of the ovary that secretes estrogen and progesterone is Corpus Luteum.
In menstrual cycle one ovum is released from either ovaries and the remaining graffian follicle converts into corpus luteum which will secret progesterone for only 7 days but if pregnancy occurs then it secret progesterone for 3 months , in this scenario how the corpus luteum will secret RELAXIN at the parturition at 9 month if it is already died and replaced by placenta?