The menstrual cycle

Question 1

How long is the menstrual cycle?

Answer 1

About 28 days

Question 2

What are the stages of the menstrual cycle?

Answer 2

• Uterine lining thickens
  + eggs mature
• Eggs finish maturing and release from ovary
  + Uterine lining stays thick
• If egg is fertilised pregnancy takes place
  + If egg isn’t fertilised uterine lining and egg are shed

Question 3

How many main stages are there in the menstrual cycle?

Answer 3

3

Question 4

What happens in the first stage? (detail)

Answer 4

• Start of cycle
• The lining of the uterus (womb) thickens, ready to support a developing baby.
• Eggs start maturing in the follicles of the ovary.

Question 5

What happens in the second stage? (detail)

Answer 5

• About 14 days after the start of the cycle:
• Egg is released from ovary in ovulation.
• Uterus lining stays thick for several days after egg release.

Question 6

What happen in the third stage? (detail)

Answer 6

• If the egg is fertilised by sperm, pregnancy takes place:
• The lining of the uterus would provide protection and food for the developing embryo.
• If the egg is not fertilised, about 14 days after ovulation:
• The uterus lining and egg are shed.
• This is the period.

Question 7

What gland controls the release of the hormones?

Answer 7

The pituitary gland

Question 8

Where is the pituitary gland?

Answer 8

The brain

Question 9

What 4 hormones are involved in the menstrual cycle?

Answer 9

• Oestrogen
• Follicle stimulating hormone (FSH)
• Luteinising hormone (LH)
• Progesterone

Question 10

What is oestrogen?

Answer 10

• Comes from ovaries in response to FSH.
• Female sex hormone.
• Stimulates uterus lining to grow again after menstruation in preparation for pregnancy.
• Inhibits FSH.
• Stimulates LH.

Question 11

What is FSH?

Answer 11

• Follicle stimulating hormone.
• Comes from pituitary gland.
• Makes eggs mature in the ovaries.
• Stimulates ovaries to produce hormones like oestrogen.

Question 12

What is LH?

Answer 12

• Luteinising hormone.
• Comes from pituitary gland.
• Stimulates the release of a mature egg from ovary.
• Levels fall after ovulation.

Question 13

What is progesterone?

Answer 13

• Comes from the empty egg follicle in the ovary after ovulation.
• Helps maintain a pregnancy if egg is fertilised.
• Inhibits FSH and LH.
• Maintains uterus lining so it can receive an embryo if the egg is fertilised.

Question 14

How does the egg change throughout the cycle?

Answer 14

• Egg matures up to about day 14.
• At abou day 14, ovulation begins.
• After about day 20, yellow body forms around the egg.
• After about day 21, yellow body breaks down.
• Egg is released during the period.

Question 15

What are the pituitary hormones?

Answer 15

• FSH
• LH

Question 16

What happens to the levels of FSH during the menstrual cycle?

Answer 16

• Increases after the period, decreasing after the uterus lining has thickened.
• Slightly increases during ovulation then decreases straight after.

Question 17

What happens to the levels of LH during the menstrual cycle?

Answer 17

• Stays low then rapidly spikes during ovulation.

Question 18

What happens to the levels of oestrogen during the menstrual cycle?

Answer 18

• Slowly increases as uterus lining builds up.
• Suddenly drops after ovulation starts.
• Slowly increases after ovulation ends.
• Drops off when period starts.

Question 19

What happens to the levels of progesterone during the menstrual cycle?

Answer 19

• Slowly increases after ovulation.
• Decreases and flatlines as period starts.

Question 20

What happens to the levels of uterus lining during the menstrual cycle?

Answer 20

• Is thin at the start of the cycle.
• Slowly thickens from days 5 to 14.
• Gets more blood after ovulation.
• Remains thick until period starts.
• Gets thin again as it is released during period.