Menstrual cycle

• During puberty the reproduction system cause secondary sexual characteristics such as pubic hair, breast development, and voice changes
• In men the testes produce the hormone testosterone which stimulates the testes to produce sperm
• In women the ovaries produce the hormone oestrogen
• Once puberty begins eggs in the ovaries start to mature every 28 days an egg is released this is called ovulation
• Every 28 days ovulation takes place ( the egg is released) in preparation for this the uterus lining becomes thick and spongy the egg now makes its way down to the uterus if sperm is present it can become fertilised if it does not become fertilised both the egg and the uterus lining becomes released this is called a period
• 1. FSH (follicle stimulating hormone) causes An egg to mature in the ovary
• 2. LH (luteinising hormone) causes this egg to be released in other words ovulation
• 3. Oestrogen (produced in the ovary) and progesterone are involved in maintaining the uterus lining in case the egg is fertilised and implants a baby
• in the first stage fsh is released by the pituitary gland fsh travels in the blood to the ovaries where it causes an egg to mature at the same time fsh triggers the ovaries to make oestrogen
• Secondly Oestrogen causes the lining of the uterus to become thick it also stops the pituitary gland from releasing any more fsh instead the pituitary gland now releases lh
• thirdly LH triggers ovulation in other words the mature egg is released
• fourth once the ovary has released the egg the ovray now produces the hormone progesterone
• Progesterone stops the pituitary gland from producing FSH and LH to prevent any more egged from maturing or being released it also keeps the uterus lining thick in case a firtilied egg implants if fertilisation does not take place the progesterone levels fall