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Protection, nourishment and gaseous exchange are important requirements for the successful development of an embryo - NSC Life Sciences - Question 4 - 2018 - Paper 1
Question 4
Protection, nourishment and gaseous exchange are important requirements for the successful development of an embryo. Describe how gaseous exchange and the nourishme... show full transcript
Worked Solution & Example Answer:Protection, nourishment and gaseous exchange are important requirements for the successful development of an embryo - NSC Life Sciences - Question 4 - 2018 - Paper 1
Step 1
Gaseous exchange in amniotic eggs
Answer
Gaseous exchange in an amniotic egg occurs through diffusion. The gases move in and out of the egg through the porous shell, specifically the allantois and chorion layers. This process allows oxygen to enter and carbon dioxide to exit, ensuring the developing embryo receives the necessary gases for metabolism.
Step 2
Step 3
Gaseous exchange and nourishment of the foetus in humans
Answer
In humans, gaseous exchange and nourishment occur primarily in the placenta. The mother's blood comes into close contact with the foetal blood, allowing for the transfer of oxygen and nutrients. Oxygen and nutrients diffuse from the mother's blood into the foetal blood in the umbilical veins, while the waste products, such as carbon dioxide, diffuse back into the mother's blood for elimination.
Step 4
Protection of the foetus in humans
Answer
The foetus develops inside the uterus and is protected by the mother's body. Antibodies from the mother's blood pass into the foetal blood, providing immunity. The placenta acts as a barrier to prevent toxins from entering the foetal bloodstream. Additionally, the amniotic fluid provides protection against dehydration and serves as a shock absorber, ensuring a suitable environment for the developing embryo.