Four hormones, one cycle

Science · The Human Body · ages 14-16

Name ______________________ Date ____________

Which hormone surge releases the egg?
- LH
- Oestrogen
- Progesterone
Which hormone grows the follicle holding the egg?
- LH
- FSH
- Progesterone
Oestrogen builds up the uterus lining.
Circle one: True False
How does combined oestrogen-plus-progestin contraception stop egg release?
- It triggers extra LH surges
- It grows extra follicles
- It keeps levels steady so no LH surge builds
What does progesterone do after ovulation?
- Releases another egg
- Keeps the lining ready
- Starts a period at once
What causes a period when there is no pregnancy?
- Rising LH bursts the lining
- FSH digests the lining
- Falling progesterone and oestrogen break the lining down
Fertility stimulation and combined contraception push the same loop in opposite directions.
Circle one: True False
Fertility stimulation can mature extra follicles. Why can twins follow, even though each embryo still needs fertilisation?
- The uterus lining doubles in thickness each month
- Sperm swim twice as fast
- More eggs can form more embryos

Answer key

For grown-ups. Fold this page away before handing over the rest.

LH · The LH surge triggers ovulation, the release of the egg.
FSH · FSH from the pituitary tells the ovary to grow a follicle.
True · Rising oestrogen from the growing follicle builds the lining.
It keeps levels steady so no LH surge builds · Steady combined levels stop the LH surge from building, so the ovary never releases the egg.
Keeps the lining ready · Progesterone keeps the lining thick and ready after ovulation.
Falling progesterone and oestrogen break the lining down · With no pregnancy the two ovarian hormones fall and the lining breaks down.
True · Combined contraception steadies levels to block the surge, while stimulation grows extra follicles.
More eggs can form more embryos · More follicles can release more eggs, and each fertilised egg can start an embryo.