The placenta plays a crucial role in the survival of the developing embryo. (i) Describe the structural features of the placenta that make it well-suited for its function. (ii) Name and explain TWO specific exchanges that take place between the mother's blood and the embryo across the placenta.
Generated by claude-sonnet-4-6 · 2026-06-26 01:07 · grounding rag
Model Answer
(i) Structural features of placenta:
The placenta is a disc-shaped tissue embedded in the uterine wall. It has villi on the embryo's side, which provide a large surface area for exchange. On the mother's side are blood spaces surrounding the villi, bringing maternal blood close to embryonic tissues.
(ii) Two exchanges across the placenta:
- Glucose and oxygen pass from the mother's blood into the embryo's blood for nutrition and respiration.
- Waste substances (like CO₂) generated by the embryo are transferred into the mother's blood for removal.
Source: Chapter 7, Section 7.3.3(b) — Female Reproductive System
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Explanation
- Examiners expect you to mention villi and blood spaces for the structural part — these are the two key anatomical features named in the textbook.
- For exchanges, the textbook explicitly states glucose & oxygen (in) and waste substances (out). Use these exact examples; do not invent others.
- This is a 3-mark question: ~1 mark for structure, ~1 mark each for the two exchanges. Keep it concise and point-based.