(a) From the fully developed foetus / placenta / foetal ejection reflex.
(b) It contains antibodies (IgA), provides immunity to the child.
Detailed Answer:
(a) The signals for parturition in humans originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This causes the release of oxytocin from maternal pituitary.
(b) The milk that comes out of the mammary glands during initinal period of lactation and after parturition is called colostrum. It contains several antibodies and nutrients and is low in fat contents. It provides immunity to the child. Therefore, it is important to feed the new born babies on colostrum. Breast feeding also recommended by doctors for bringing up a healthy baby.
