Question

Name and describe very briefly, the stages in the development of the human embryo. [5 MARKS]

Answer 1

Naming: 2 Marks
Description: 3 Marks

Stages in the development of human embryo:
Egg (Ovum) - Unfertilized stage, released from ovary.
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Zygote - Fertilized egg, 1-cell (unicellular) state.
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Morula - A spherical mass of cells.
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Trophoblast - A single layer of cells enclosing an enlarged cavity.
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Blastocyst - An inner cell mass which projects centrally from the surrounding cellular layer.
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Embryo - A tiny organism about the size of a large pea.
(3 weeks)
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Advanced embryo - Heart and blood vessels have formed (but no limbs).
(5 weeks)
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Foetus (8 weeks) - Limbs have appeared. Some resemblance with a baby.
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Infant - Born at the end of nearly 4 weeks.