Question

Describe the process of parturition in humans.

Answer 1

Hint: Parturition: It is the process of delivery of the foetus or childbirth.
It is induced by a complex neuroendocrine mechanism.
It involves three stages:
1. Stage 1: Dilation of cervix
2. Stage 2: Delivery of new born
3. Stage 3: Shedding of placenta.

Complete answer:
 At the end of an average 9 months of gestation period vigorous uterine contractions lead to the delivery of the foetus and this process is called parturition.
A developing foetus secretes some hormones from its adrenal glands; these hormones diffuse into the maternal blood and collect to stimulate the release of oxytocin which is a birth hormone from the mother’s posterior pituitary.
Oxytocin causes the forceful contraction of smooth muscles of the myometrium called labour pains, which pushes the baby gradually out through the dilated cervix and vagina with the head first.
The reflex between the uterine contraction and oxytocin secretion causes stimulation and results in stronger and stronger contractions.
The foetal membranes burst and amniotic fluid is
This expulsion stage lasts about 20 minutes to one hour.
 It is followed by a placental stage of 10-45 minutes during which the umbilical cord, placenta and foetal membranes are expelled as decidua or after birth.
It is because after parturition the uterus reduces in size causing detachment of placenta.
The umbilical cord is tied and then cut which is finally shrunken up into a scar called umbilicus or navel.

Note: The mammary glands of females differentiate during pregnancy and start producing milk.
The production of milk is known as lactation.
This helps the mother in feeding the newborn.
Colostrum is the milk produced at the initial few days of lactation.