IGCSE Biology glossary
Oestrogen
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Definition
A hormone produced by the ovaries that controls the development of female secondary sexual characteristics during puberty and plays a key role in the menstrual cycle, where it stimulates the repair and thickening of the uterus lining after menstruation.
What to include in an exam answer
In the menstrual cycle, oestrogen repairs the uterus lining and triggers ovulation. It is produced by the ovaries. Do not confuse with progesterone, which maintains the thickened lining.
Example in context
Describe the role of oestrogen in the menstrual cycle (2 marks): Oestrogen is produced by the ovaries and causes the uterus lining to thicken and repair after menstruation. A surge in oestrogen triggers ovulation around day 14.
Related syllabus topic
Reproduction