Ovarian and uterine cycles coordinate follicle growth, ovulation, endometrium maintenance and menstruation through FSH, LH, estrogen and progesterone feedback loops.
Coverage 2013–2024 · Updated 16 Jul 2026
The menstrual cycle combines ovarian and uterine cycles controlled by FSH, LH, oestradiol and progesterone through negative and positive feedback.
| Stage | Hormonal control and linked event |
|---|---|
| Follicular phase | FSH promotes follicle growth; the follicle secretes oestradiol, which rebuilds the endometrium and usually inhibits FSH |
| Ovulation | Sustained high oestradiol produces positive feedback, causing an LH surge that triggers ovulation |
| Luteal phase | LH supports the corpus luteum; progesterone maintains the endometrium and inhibits FSH/LH |
| Menstruation if no pregnancy | Corpus luteum breaks down; progesterone and oestradiol fall, so the endometrium is shed and inhibition is removed |
A sharp LH peak follows the high-oestradiol positive-feedback switch and occurs just before ovulation.
Feedback direction changes with hormone concentration and cycle stage; oestradiol is not always a positive-feedback signal.
This objective is assessed through structured response, commonly using Sketch / Identify / Outline.
Sketch / Identify / Outline / Explain
Build the answer around this relationship: FSH promotes follicle development and estrogen secretion.
Confusing LH with FSH or progesterone when identifying the hormone that triggers ovulation.
Representative question
Explain the roles of specific hormones in the menstrual cycle, including positive and negative feedback mechanisms.
Core D3.1 route: reproduction creates offspring, gametes or pollen move, fertilization or germination follows, and the consequence is variation, embryo formation, seed production, or successful early growth.
Core D3.1 exam questions usually combine reproduction strategy with gamete formation, fertilization, human cycles, IVF, plant pollination, or seed germination. Treat each answer as a route: name the process, say what moves or changes, then give the biological consequence.
