| Stages of Menstrual Cycle |
|---|
| 1. Menstruation - uterine lining + unfertilised egg → break down and are shed with some blood |
| 2. After Menstruation - ovary produce hormone called oestrogen - oestrogen → causes uterine lining to repair and thicken - high oestrogen concentration → leads to ovulation |
| 3. Ovulation - on 14th day → an ovary → releases an egg into the oviduct → through process known as ovulation - 2 ovaries take turns to release an egg |
| 4. After Ovulation - ovaries produce hormone → progesterone Functions of progesterone: → prevents ovulation + further development of eggs → causes uterine lining to thicken further, preparing it for implantation and growth of embryo. - if no fertilisation occurs → progesterone production decreases. - uterine lining breaks down and whole cycle repeats |
| 
Note
- since implantation (if fertilisation occurs) happens 5 days after fertilisation, the level of progesterone peaks at around day 22 → refer to the function of progesterone which is to thicken uterine lining further which prepares uterus for implantation.
- must come down at around day 27 → prepare for menstruation again.
Sample
- when answering question → assume menstrual cycle of same female remains same every month