Edexcel iGCSE Biology-4.10 B Roles of FSH & LH in the menstrual cycle- Study Notes- New Syllabus
Edexcel iGCSE Biology-4.10 B Roles of FSH & LH in the menstrual cycle- Study Notes- New syllabus
Edexcel iGCSE Biology-4.10 B Roles of FSH & LH in the menstrual cycle- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
4.10B understand the roles of FSH and LH in the menstrual cycle
Roles of FSH and LH in the Menstrual Cycle
🌟 Introduction
The menstrual cycle (~28 days) is hormonally controlled.
FSH (Follicle Stimulating Hormone) and LH (Luteinising Hormone) are secreted by the pituitary gland.
They act on the ovaries to regulate egg maturation and ovulation.
🌺 FSH (Follicle Stimulating Hormone)
- Source: Pituitary gland
- Role:
- Stimulates development of ovarian follicles (each containing an egg)
- Stimulates follicles to produce oestrogen
- Peak: Early in the cycle → helps start the egg maturation process
🌼 LH (Luteinising Hormone)
- Source: Pituitary gland
- Role:
- Triggers ovulation (release of the egg from the follicle) around day 14
- Stimulates formation of corpus luteum from the empty follicle
- Corpus luteum secretes progesterone → maintains uterine lining
- Peak: Mid-cycle → triggers egg release
📊 Summary Table
| Hormone | Source | Main Role | Timing/Peak |
|---|---|---|---|
| FSH | Pituitary gland | Matures ovarian follicles, stimulates oestrogen production | Early cycle (day 1–14) |
| LH | Pituitary gland | Triggers ovulation, forms corpus luteum | Mid-cycle (~day 14) |
📌 Quick Recap
– FSH: starts follicle development & oestrogen secretion.
– LH: triggers ovulation & corpus luteum formation.
– Together → regulate the menstrual cycle and prepare for possible pregnancy.