The Menstrual Cycle

• What is the endocrine system responsible for?

  Releasing hormones into the bloodstream
• What hormone do the testes produce?

  Testosterone
• What does testosterone stimulate in men?

  Production of sperm
• What hormone do the ovaries produce?

  Estrogen
• What happens to eggs in the ovaries after puberty?

  They start to mature
• How often does ovulation occur?

  Every 28 days
• What is ovulation?

  Release of an egg from the ovary
• What happens to the uterus lining during ovulation?

  It becomes thick and spongy
• What occurs if the egg is fertilized?

  It can implant into the uterus wall
• What happens if the egg is not fertilized?

  Both the egg and uterus lining are released
• What are the four key hormones involved in the menstrual cycle?

  • Follicle stimulating hormone (FSH)
  • Luteinizing hormone (LH)
  • Estrogen
  • Progesterone
• What does FSH do in the menstrual cycle?

  Causes an egg to mature in the ovary
• What does LH do in the menstrual cycle?

  Triggers the release of the egg
• What role does estrogen play in the menstrual cycle?

  Maintains the uterus lining and inhibits FSH
• What is the effect of progesterone in the menstrual cycle?

  Keeps the uterus lining thick and inhibits FSH/LH
• What happens to progesterone levels if fertilization does not occur?

  Progesterone levels fall
• What is the result of falling progesterone levels?

  The uterus lining and egg are released
• How do FSH and estrogen levels interact during the menstrual cycle?

  Estrogen inhibits FSH production as it rises
• What triggers the peak of LH in the menstrual cycle?

  Increase in estrogen levels
• What happens to hormone levels during a woman's period?

  FSH and LH levels are low
• What are the stages of hormone interaction in the menstrual cycle?

  1. FSH is released, causing egg maturation.
  2. Estrogen is produced, thickening the uterus lining.
  3. Estrogen inhibits FSH and triggers LH release.
  4. LH triggers ovulation.
  5. Progesterone maintains the uterus lining.
  6. If no fertilization, progesterone falls, leading to menstruation.
• What can you be asked to interpret in an exam regarding the menstrual cycle?

  Graphs of hormone levels
• What happens to the levels of FSH during the menstrual cycle?

  FSH levels rise and then fall
• What is the relationship between estrogen and FSH levels?

  Estrogen inhibits FSH production
• What happens to progesterone levels after ovulation?

  Progesterone levels rise
• What is the significance of the menstrual cycle?

  It prepares the body for potential pregnancy