AQA GCSE Biology · 8461
Specification 4.5.3.4 · Paper 2
The repeating sequence in which an egg matures and may be released while the uterus lining breaks down, rebuilds and is maintained.
Revise: The Menstrual Cycle and Hormonal ControlThe menstrual cycle begins at puberty and is controlled by hormones carried in the blood. In an average cycle of approximately 28 days, an egg matures in an ovary, one egg is released and the lining of the uterus changes in preparation for a possible pregnancy. The timing varies, so day 14 should be treated as an approximate time of ovulation rather than a rule for every cycle.