Question

Hormone oxytocin at the time to birth acts on uterus by
(A)Stimulating the smooth muscles to contract
(B)Reducing the lumen of the uterus
(C)Increasing the movement of foetus
(D)Producing rhythmic movements in uterus

Answer 1

In response to relaxation of the cervix and uterus throughout labour and with stimulation of the nipples by breastfeeding, oxytocin is stimulated to release as a hormone. This assists with pregnancy, bonding with the infant, and the development of milk.

Complete answer:
First, we should know about oxytocin to answer this question. Oxytocin is a neuropeptide and a hormone peptide. In the hypothalamus, it is usually developed and produced by the posterior pituitary. It plays a significant role in the time after childbirth, in pair connection, sexual reproduction, and childbirth.
Now, let us find the solution from the options-
- Pressure of the head of the foetus on the cervix and the sending of hypothalamus impulses to cause oxytocin secretion from the posterior pituitary. Oxytocin (OT) or prostaglandins together induce heavy contraction of the uterine muscle, pulling the foetus downward.
-The foetus is removed from the uterus by a powerful push of contraction of the uterine wall; not by lowering the uterine lumen or increasing its motion. Thus, option B and C are not the correct option.
- Prostaglandins induce a contraction in the smooth muscles of the uterine wall at birth. Thus, option D is not the correct option.

Hence, the correct answer is option(A).

Note: Estrogen was found to enhance oxytocin secretion and to enhance the activity in the brain of its receptor, the oxytocin receptor. A single dose of estradiol was found to be adequate in women to increase endogenous oxytocin levels.