The menstrual cycle

-Hormones-> control functions of many of your body organs and control activity of your individual cells

-Hormones made in womens brain and ovaries,control mentrual cycle 

- Average length of menstrual cycle- 28 days 

-Each month, lining of womb thickens- support developing baby

-Same time- egg starts maturing in ovary

-After egg starts maturing- its released from ovary 

-Lining of womb stays thick for several days after egg has been released 

- If egg fertilised by sperm-pregnant

-Lining of womb provides protection and food for developing embryo 

-If egg isn't fertilised->dead egg and lining of womb is shed from body-period

-Changes are brought about by hormones-made and released by pituritary glands and ovaries 

-Once a month, a surge of hormones from pituritary gland in brain starts egg maturing in ovaries 

-Hormones also stimulate ovaries to produce female sex hormone- oestrogen 

-FSH-> secreted by piturity glands. Makes egg mature and stimulates ovaries to produce oestrogen 

-Oestrogen-> Made and secreted by ovaries. Stimulates lining of womb to build up. Stimulates piturity gland to make another hormone called LH

-LH-> Secreted by piturity glands. Stimulates release of a mature egg from one of the ovaries in the middle of the menstrual cycle (day 14)

-Hormones produced by piturity glands and ovary act together to control what happens in the menstrual cycle

-As oestrogen levels rise they inhibit (slow down) the production levels of FSH and encourage production of LH by piturity glands 

-When LH levels reach a peak in the middle of a cycle-they stimulate the release if a mature egg