Final answer:
Oxytocin is a nonapeptide hormone produced by the pituitary gland important for inducing uterine contractions during childbirth and stimulating milk release during breastfeeding. It is also associated with bonding and emotional closeness.
Step-by-step explanation:
Oxytocin is a peptide hormone that is secreted by the pituitary gland and plays a vital role in inducing uterine contractions during childbirth and the milk ejection reflex (let-down) during breastfeeding. It is also associated with social bonding, attachment, and several aspects of reproduction and post-reproductive behaviors. Unlike steroids or thyroid hormones, it does not belong to the lipid-based hormone group but is part of the group of hormones made from amino acids - specifically, it is a nonapeptide (a peptide containing nine amino acids). Additionally, oxytocin is involved in functions such as emotional bonding and may influence feelings of love and closeness, contributing to parent-newborn bonding.
During the process of childbirth, oxytocin receptors in the uterus increase in number, becoming more sensitive to its effects. This leads to a positive feedback mechanism where oxytocin stimulates contractions, pushing the fetal head towards the cervix, thereby stretching it and causing more oxytocin release until the baby is born.