Hi
The secretion of FSH & LH (from the pituitary gland) as well as the ovarian hormones (progesterone and oestrogen) is controlled by a NEGATIVE FEEDBACK MECHANISM. The signalling mechanism is the increased concentration of each hormone in the blood and this increase in one hormone will negatively affect the other.
Under the influence of FSH (follicle stimulating hormone), a Graafian follicle will develop and this will produce oestrogen. LH will cause the Graafian follicle to form the corpus luteum which will secrete progesterone.
The increase in the concentration of the progesterone as well as the oestrogen will activate a negative feedback mechanism which will stop the pituitary (hypophysis) from secreting LH and FSH.
As there is no FSH, the Graafian follicle will not develop and no oestrogen and later progesterone will be released by the ovary.
Because of the low levels of oestrogen & progesterone, the secretion of FSH & later LH is no longer suppressed and the whole cycle begins all over again.
Oh Gosh My Grades 