Chapter 223 of 2363 min read
Fertilisation, implantation, pregnancy, parturition, lactation
Why this is asked: Early pregnancy runs on hCG: it is what keeps the corpus luteum from degenerating, and it is what a pregnancy test actually detects, buying time until the placenta itself takes over progesterone production later on. Parturition is one of the syllabus's rare genuine positive-feedback loops — signals from the fully developed foetus trigger mild contractions, which release oxytocin, which strengthens contractions further — the opposite of the negative feedback most hormone regulation in this chapter runs on.
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- •Twins are born to a family that lives next door to you. The twins are a boy and a girl. Which of the following must be true?
- •Find the correct statements: (A) In human pregnancy, the major organ systems are formed by the end of 12 weeks. (B) In human pregnancy, the major organ systems are formed by the end of 8 weeks. (C) In human pregnancy, the heart is formed after one month of gestation. (D) In human pregnancy, limbs and digits develop by the end of the second month. (E) In human pregnancy, the appearance of hair is usually observed in the fifth month. Choose the correct answer from the options given below:
- •Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Breast-feeding during the initial period of infant growth is recommended by doctors for bringing up a healthy baby. Reason R: Colostrum contains several antibodies absolutely essential to develop resistance for the newborn baby. In the light of the above statements, choose the most appropriate answer from the options given below:
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