paper 2 bio

• fsh - causes an egg to mature in the ovary
• lh - causes the mature egg to be released (ovulation)
• oestrogen and progesterone maintain the uterus lining incase an egg is fertilised and implants
• fsh is released by the pituitary gland and travels in the blood to the ovaries where it causes an egg to mature. fsh triggers the ovaries to make oestrogen
• oestrogen stops the pituitary gland from releasing any more fsh. instead the pituitary gland releases lh which triggers ovulation
• instead the ovary then produces progesterone after ovulation. the progesterone stops the pituitary gland from releasing more fsh and lh. this prevents eggs from maturing and being released