Question

From where the parturition signals arise-mother or foetus? Mention the main hormone involved in parturition.

Answer 1

Signals of parturition

Parturition is the expulsion of the fully developed foetus from the uterus after the completion of the gestation period. The signals for parturition originate from the ‘fully developed foetus’ and the placenta which induce mild contractions called foetal ejection reflex.

Foetal-ejection reflex

Fully developed foetus pushes down the birth canal, causing stretching of the cervix. This generates nerve impulse which stimulates the hypothalamus. Hypothalamus in turns causes the posterior pituitary to release oxytocin, also called as birth hormone. Oxytocin causes the uterine muscles to contract leading to parturition.

Final answer

Signals of parturition: Fully developed foetus Hormone involved in parturition: Oxytocin