Describe the sequence of hormonal interactions in the menstrual cycle.

FSH is released to mature and egg, causing OESTROGEN to be released, thickening the uterus lining. This inhibits FSH, as LH is released until the levels reach its peak. When the egg is released, OESTROGEN and PROGESTERONE is released to thicken and maintain the lining, stopping the secretion of LH. If the egg is fertilised, PROGESTERONE and OESTROGEN levels stay high. If the egg isn't fertilised, PROGESTERONE and OESTROGEN levels decrease and the process repeats.