Question

What is the correct sequence for parturition to occur?

(a) Signal from fetus and placenta → Uterine contractions → Release of oxytocin → Rise in oxytocin secretion → Powerful contractions → Parturition

(b) Uterine contractions → Release of oxytocin → Rise in oxytocin secretion → Powerful contractions → Signal from fetus and placenta → Parturition

(c) Signal from fetus and placenta → Release of oxytocin → Uterine contractions → Rise in oxytocin secretion → Powerful contractions → Parturition

(d) Release of oxytocin → Uterine contractions → Signal from fetus and placenta → Rise in oxytocin secretion → Powerful contractions → Parturition

The question was posed to me in an internship interview.

This interesting question is from Human Reproduction topic in portion Human Reproduction of Biology – Class 12

Answer 1

Right answer is (c) Signal from fetus and placenta → Release of oxytocin → Uterine contractions → Rise in oxytocin secretion → Powerful contractions → Parturition

The explanation: Parturition starts with the signal released by the fetus and the placenta. These act on the pituitary to release oxytocin. Oxytocin acts as a stimulant leading to contractions of the uterine muscles. The uterine contractions feedbacks to release more oxytocin from the pituitary. This results in more powerful contractions of the uterus until the baby is delivered in the process of parturition.