Why does the uterus prepare its lining every month even before it is known whether fertilisation will occur?
Generated by claude-sonnet-4-6 · 2026-06-26 01:06 · grounding rag
Model Answer
The uterus prepares its lining every month because fertilisation can potentially occur after each ovulation. Since one egg is released every month, the uterine lining becomes thick and spongy, richly supplied with blood, to nourish the embryo in advance. The body cannot wait to confirm fertilisation before preparing, as the embryo needs immediate implantation.
Source: Chapter 7, Section 7.3.3(c)
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Explanation
- The key idea is advance preparation: the uterus must be ready before it is known whether fertilisation has occurred, because the embryo needs to implant into a prepared lining immediately.
- Mention both what the lining does (thickens, becomes spongy, richly supplied with blood) and why (to nourish/receive the fertilised egg).
- If fertilisation does not occur, this lining breaks down as menstruation — that contrast is a useful addition if word count allows.
- Examiners look for: (1) monthly egg release → monthly uterine preparation, and (2) purpose of the lining (nourishment of embryo).