Question
Biology Question on Parturition And Lactation
The foetal ejection reflex in humans triggers the release of
oxytocin from foetal pituitary
human chorionic gonadotropin (hCG) from placenta
human placental lactogen (hPL) from placenta
oxytocin from maternal pituitary.
oxytocin from maternal pituitary.
Solution
Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscles and causes stronger uterine contractions, which in turn stimulates further secretion of oxytocin. The stimulatory reflex between the uterine contraction and oxytocin secretion continues resulting in stronger and stronger contractions. This leads to expulsion of the baby out of the uterus through the birth canal i.e., parturition.