Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only.)
The hormone that induces vigorous contractions of the uterus in a pregnant mother is:
Topic: Oxytocin
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Answer
(c) Oxytocin.
OXYTOCIN, from the POSTERIOR lobe of the pituitary, causes the powerful contractions of the uterine muscles during labour that push the baby out. It is sometimes called the birth hormone.
The other three are all involved in pregnancy, which is what makes them plausible — so separate them by FUNCTION: OESTROGEN — develops the female secondary sexual characteristics and repairs the uterine lining after menstruation. PROLACTIN — stimulates the MAMMARY GLANDS to produce milk (oxytocin then ejects it). PROGESTERONE — MAINTAINS pregnancy by keeping the uterine lining thick and, importantly, PREVENTS contractions. Its level falls just before labour, which is what allows oxytocin to act.
Note the neat pairing examiners like: progesterone stops contractions, oxytocin starts them.
Oxytocin.