Question

Which is not an important component of the initiation of parturition in humans?
A. Synthesis of prostaglandins
B. Release of oxytocins
C. Release of prolactin
D. Increase in estrogen and progesterone ratio

Answer 1

Hint: Parturition is the act of expelling the full-term young one from the mother’s uterus at the end of gestation. Gestation is completed in about 280 days from the start of the mother's last menstruation. It is important that the baby be born when it is mature.

Complete answer: The fetus signals that it is mature by secreting certain hormones. The latter diffuse across the placenta into the mother’s blood, where they cause the secretion of oxytocin from her posterior pituitary. Oxytocin stimulates the uterine contractions. This provides the force to expel the baby from the uterus, causing birth. Oxytocin also stimulates the placenta to secrete prostaglandins. Prostaglandins stimulate more contractions, by positive feedback induce continuation of oxytocin and prostaglandins production.
So, the correct answer is option C-Release of prolactin
Additional information :
The forceful muscular contractions of the uterine wall leading to parturition are called labor. The term is appropriate as it is a period of work at the expense of considerable energy. About two weeks before birth, the foetus normally settles head down into the pelvic cavity. On the completion of gestation, labor starts. It causes labor pains. Dilation, expulsion, placental are stages of parturition.

Note: Sometimes the foetus fails to come out and a surgical procedure, called a cesarean section, is needed. The baby is removed through a cut given in the mother’s abdomen. Secretion and storage of milk begin after the birth of the young one, usually within 24 hours, under the influence of prolactin.