Wing asked in 科學及數學生物學 · 1 decade ago

Science Question

1)State the importance of placenta.

2)Explain why doctor do not recommend pregnant women to do vigorous exercise.

3)Why is it important for the foetus to come out of the mother with the head first during birth?

4)Why does blood come out from vagina when menstruation?

5)A girl had sex with a boy last month. Her menstruation should have occurred last week. If you were their friend,what advice would you give to them?Give THREE examples.

1 Answer

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  • 莫愁
    Lv 6
    1 decade ago
    Favorite Answer

    1)State the importance of placenta.Ans : (1) It is a place for material exchanges between fetus and mother. Nutrient will diffuse from maternal blood to fetus blood via placenta. Metabolic wastes such as carbon dioxide will diffuse from fetus blood to maternal blood via placenta. (2)It acts as a filter to filtrate off toxic substances such as hormone and virus. However, it is not a very good filter sometimes due to some viruses such as rubella able to pass throught it.

    2)Explain why doctor do not recommend pregnant women to do vigorous exercise. Ans : Sometimes during exercises will accidently trigger the vigorous contraction of endometrium, leading to sudden born of baby. Besides when doing vigorous exercise, the attachment of zygote and endometrium due to implementation may be disturbed. Finally ,miscarriage(流產) occurs

    3)Why is it important for the foetus to come out of the mother with the head first during birth? Ans : to prevent the umbilical cord accidentally tangling (糾纏) baby's neck. This ensures safe delivery of baby.

    4)Why does blood come out from vagina when menstruation? Ans : This is due to the slough off of the endometrium casued by the degeneration of corpus luteum. Without corpus luteum, no progesterone and oestrogen will be produced. Hence endometrium cannot grow and thicken further, leading to endometrium slough off.

    5)A girl had sex with a boy last month. Her menstruation should have occurred last week. If you were their friend,what advice would you give to them?Ans : She may be pregnancy due to late menstruation and should be verified by obstetrician(婦產科醫生). Give THREE examples. (不明白問些什麼) .

    I hope you will find them helpful.

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