The Menstrual Cycle

• During Puberty reproductive hormones cause secondary characteristics to develop such as pubic hair.
• Testes produce the hormone testosterone
• ovaries produce the hormone oestrogen
• one puberty starts eggs in the ovaries start to mature. This is called Ovulation
• every 28 days an egg is released
• in ovulation the ovary releases an egg
• in preparation for ovulation the uterus lining becomes thick and spongy
• if the egg is not fertilised then the uterus lining and egg are released. this called a period.
• FSH causes the egg to mature in the ovary.
• LH causes the egg to be released i.e ovulation.
• Oestrogen, produced by the ovary, and progesterone are involved in maintaining the uterus lining, incase the egg is fertilised and implants.
• First stage:

  1. FSH is released by the pituitary gland
  2. FSH travels in the blood to the ovaries where it causes the egg to mature
  3. at the same time, FSH trigger the ovaries to make Oestrogen
  4. Oestrogen causes the uterus lining to become thick and stop the pituitary gland releasing FSH
• Second stage:

  1.Now the pituitary gland releases LH

  2.LH triggers ovulation

  3.once the ovary has released this egg the ovary now produces progesterone

  4.progesterone stops the pituitary gland from releasing FSH and LH AND keeps the uterus lining thick

  5. if the fertilisation doesn't take place progesterone levels fall and the woman has a period