Tag: parturition and lactation

Oxytocin is the hormone that stimulates powerful uterine contractions, and its concentration increases significantly to determine the onset and progression of labor (childbirth).

Birth occurs when foetal development is complete, typically around 38-40 weeks of gestation. The zygote is the initial single-cell stage formed at fertilization, not the developed stage ready for birth. The uterus is the organ, not the developing organism. At birth, the foetus has developed all major organ systems and is ready to survive outside the womb. Thus, completion of foetal development is the prerequisite for birth.

The process of delivery of foetus is called as parturition. Parturition is the act of expelling the full-term foetus from the mother's uterus at the end of gestation. In this process fully developed foetus produces foetal ejection reflex which stimulates pituitary to release oxytocin hormone. This hormone causes vigorous uterine contraction that leads to the delivery of feotus. This process is also known as the delivery of the foetus when the pregnancy period gets over. The importance of parturition is that the event results in the foetus to come out of the womb. The process is accompanied with the onset of lactation.

Salmonella atra is an amphibian having one of the longest gestation periods among animals existing on this earth. They have a gestation period between 36-48 weeks.

The horse has a gestation period of around 342 days whereas it is around 289 days for the cow.

Oxytocin is a hormone which is released from the pituitary gland. It is responsible for the muscular contraction which occurs during the parturition. The fully developed baby exerts a pressure on the walls of the uterus and as a result, it signals the pituitary gland to release oxytocin. The muscular contractions are responsible for the expulsion of the baby out of the uterus.

Parturition or childbirth is the event of bringing a child into the world from the uterus of the mother. It involves forceful muscle contractions of the uterine wall which push the child out of the womb through the vaginal canal. Several events take place after the birth of the child, including expulsion of the placenta, umbilical cord, and fetal membrane.

Foetal ejection reflex occurs at the time of parturition and are gentle uterine contactions produced by the placenta. This may occur due to extremely high levels of adrenaline during childbirth. Since parturition is a neuro-endocrine process, oxytocin is released by the neurohypophysis of maternal pituitary which stimulates stronger contractions of the uterus and induces labour pain, with decreasing progesterone levels and marks the end of the gestation period. Hence, the correct answer is 'Release of oxytocin from maternal pituitary'.

The ectoderm, which is made up of columnar cells, forms the epidermis of the skin, nervous system, cornea, lens, retina, salivary glands and the enamel of teeth. The mesoderm gives rise to the dermis of skin, gonads, heart, blood and lymph, kidney, reproductive ducts and most of the muscles. The last layer, the endoderm gives rise to the gastric and intestinal glands, liver, pancreas, lining of the middle ear.

The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus but also serves to facilitate the exchange of nutrients, water, and biochemical products between mother and fetus. Amniotic fluid is present from the formation of the gestational sac. The forewaters are released when the amnion ruptures prior to childbirth.