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Reproductive Health — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYReproductive Health1 Mark
Question
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: Generally, a woman does not conceive during the lactation period.
Reason: The hormone 'prolactin' initiates and maintains lactation in a postpartum woman.
✓

Answer

  1. Both assertion and reason are true, but reason is not the correct explanation of assertion.

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Explanation:

Milk secretion is maintained as long as breast feeding, and hence hormone production continues. A woman does not conceive during the lactation period because lactation stimulates prolactin secretion and there is evidence that prolactin inhibits GnRH secretion, and antagonises the action of gonadotrophins on the ovaries. Ovulation is inhibited, and the ovaries are inactive, so estrogen and progesterone output falls to low levels. Thus, during lactation a woman does not conceive. Only 5-10% chances are there during lactation period. This can also be interpreted as mechanism devised by nature so that mother can look after the new born child by providing it with milk.

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