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 holding oestrogen high all month stop egg release?
- It dissolves the ovaries
- It speeds the cycle up
- It stops the LH surge happening
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 drugs and contraceptive pills push the same loop in opposite directions.
Circle one: True False
Fertility treatment adds hormones that grow extra follicles. Why can twins follow?
- The uterus lining doubles
- Sperm swim twice as fast
- More follicles can release more eggs

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 stops the LH surge happening · No oestrogen peak means no LH surge, so the ovary never releases the egg.
Keeps the lining ready · Progesterone from the leftover follicle keeps the lining thick and ready.
Falling progesterone and oestrogen break the lining down · With no pregnancy the two ovarian hormones fall and the lining breaks down.
True · Contraception holds hormones steady to stop release, while fertility treatment adds hormones to grow follicles.
More follicles can release more eggs · Extra follicles mean extra eggs, so more than one embryo can start.