Health Sciences 4320A/B Lecture Notes - Lecture 9: Umbilical Cord, Cervical Canal, Posterior Pituitary

• School: Western University
• Department: Health Sciences
• Course: Health Sciences 4320A/B
• Professor: Christine Bell

Document Summary

Childbirth: parturition process during which the fetus, placenta, and fetal membranes are expelled from the reproductive tract. Labour sequence of involuntary uterine contractions resulting in dilation of the cervix and expulsion of the fetus/placenta. Hormones of childbirth: positive feedback process of hormones, oxytocin released from posterior pituitary. Elicits peristaltic myometrium contractions to push baby down. Fetus" head pushes against cervix with every contraction, causing release of more oxytocin. More oxytocin = frequent and stronger contractions: prostaglandins released from decidua. Sensitizes myometrium to oxytocin: estrogens released from chorion and syncytiotrophoblast. Stimulates the release of oxytocin and prostaglandins. Made from fetal contribution of the placenta fetus releases corticotropin releasing hormone (crh) from hypothalamus, which stimulates acth, which stimulates cortisol, which triggers estrogen production by the placenta. Stages of labour: dilation progressive dilation of cervix. As cervix dilates, mucous plug falls out gradually or suddenly indication that labour is around the corner. Ends when cervix is completely dilated at 10cm.