Tag: pregnancy and birth

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.

During pregnancy in the human, hormones such as relaxin allows the pelvic bones to be more flexible for delivery. The gap of the symphysis pubis, normally is 4–5 mm but during pregnancy there is an increase by at least 2–3 mm. The symphysis pubis separates to some degree during childbirth hence pubic symphysis is an amphiarthrodial joint.

Oxytocin is a peptide hormone secreted by the posterior pituitary. It is also a neuropeptide, used for inter-neuron communication. This hormone is responsible for secretion or ejection of milk. PRH or prolactin releasing hormone is responsible for the release of Prolactin or PRL, which is a hormone responsible for milk production. Progesterone inhibits lactation during pregnancy.

In medical terms, the third stage of labor is known as the afterbirth. This stage involves the expulsion of the placenta, umbilical cord, and fetal membranes after the baby has been delivered.