The Menstrual Cycle

• What releases hormones into the bloodstream?

  Glands
• Where do hormones travel to trigger effects?

  Specific target organs
• What do scientists call the system of hormone release and effect?

  The endocrine system
• What is a really important role of the endocrine system?

  Human reproduction
• During what life stage do reproductive hormones cause secondary sexual characteristics to develop?

  Puberty
• Which hormone do the testes produce?

  Testosterone
• What does testosterone stimulate the testes to produce?

  Sperm
• Which hormone do the ovaries produce?

  Estrogen
• What begins to happen to eggs in the ovaries once puberty begins?

  They start to mature
• What is the release of an egg called?

  Ovulation
• How often is an egg released on average?

  Every 28 days
• What is the release of an egg every 28 days part of?

  The menstrual cycle
• How often does ovulation take place?

  Every 28 days
• What happens to the uterus lining in preparation for egg release?

  It becomes thick and spongy
• Where does the egg make its way to after being released?

  The uterus
• What happens if sperm is present when the egg is in the uterus?

  The egg can be fertilized
• What two things are released if the egg does not get fertilized?

  The egg and uterus lining
• What is the release of the egg and uterus lining called?

  A period
• How many key hormones are described as playing a role in the menstrual cycle?

  Four
• What is the abbreviation for follicle stimulating hormone?

  FSH
• What does FSH cause to happen in the ovary?

  An egg to mature
• What is the abbreviation for luteinizing hormone?

  LH
• What does LH cause to happen to the egg?

  Causes the egg to be released
• What is another term for the release of the egg?

  Ovulation
• Which gland releases follicle stimulating hormone?

  The pituitary gland
• Where does FSH travel to from the pituitary gland?

  To the ovaries via the blood
• What does FSH trigger the ovaries to make?

  Estrogen
• What effect does estrogen have on the lining of the uterus?

  Causes it to thicken
• What effect does estrogen have on the pituitary gland's release of FSH?

  It stops the release
• What is triggered by LH?

  Ovulation
• What hormone does the pituitary gland release instead of FSH?

  Luteinizing hormone (LH)
• What happens once the ovary releases its egg?

  The ovary produces progesterone
• What two effects does progesterone have?

  Stops FSH/LH release; keeps uterus lining thick
• What happens if fertilization does not take place to progesterone levels?

  The level of progesterone falls
• If the level of estrogen increases, what will happen to the level of FSH?

  The level of FSH will fall
• What happens when progesterone levels fall?

  Uterus lining and egg are released
• During the menstrual cycle, what relationship can be observed between estrogen and LH levels?

  Estrogen triggers the release of LH
• How do estrogen and progesterone affect the uterus lining?

  Estrogen thickens, progesterone maintains it
• If a woman has consistently low levels of LH throughout her cycle, what process will likely be affected?

  Ovulation
• If a woman's progesterone levels remain high for an extended period, what is a likely explanation?

  She is pregnant