Parturition and Lactation – Class 12 | Chapter – 3 | Biology Short Notes Series PDF

Parturition and Lactation: The process of Parturition starts when gestation is completed by the embryo which is about 280 days its time for process of birth of the baby. At the time of birth there are powerful contractions of the muscles of the uterus and the baby arrives with the head first out. After the birth of the infant the blood vessels in the umbilical cord shrink. They are tied in a knot and cut. After a while, the placenta breaks from the uterus and is expelled out. The uterus regains its normal shape after some days.


Lactation: In this process of lactation mammary gland starts production of milk. Secretion and storage of milk is carried out under the influence of prolactin. Ejection of milk is stimulated by oxytocin. The first milk which comes from the mammary glands of the mother just after the child birth is called colostrum. Colostrum is the first milk which comes from the mammary glands of the mother just after childbirth, for 2-3 days. Colostrum contains antibodies that provide passive immunity to the newborn infant. The main constituents of human milk are fat, caesin, lactose, mineral salts and vitamins.

Process of Parturition and Lactation

  • Parturition is the process of delivery of feotus because of vigourus contraction of uterus.
  • Once the fully developed feotus gives fetal ejection reflex, the release of oxiticin hormone from pituitary occurs.
  • The oxytocin results in strong contraction of uterus wall which leads to the expulsion of feotus.

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By Team Learning Mantras