Fetal membranes umbilical cord and placenta Dr Sanjaya

Fetal membranes, umbilical cord and placenta Dr. Sanjaya Adikari Department of Anatomy

Objectives • Describe the structure and function of the placenta, umbilical cord and membranes

Decidual plate Chorionic plate

Cotyledon (15 -20) Chorionic villi Lacunar/intervillous spaces

Macroscopic appearance of placenta

Placenta – fetal surface

Placenta – maternal surface

Placenta and membranes

What is placental barrier?

Placental barrier 2 1

Functions of the placenta • Exchange of gases • Removal of metabolic products • Nutrition • Transmission of maternal Ab • Production of hormones

Placental hormones • Human chorionic gonadotropin-h. CG • Progesterone • Oestrogens • Human chorionic somatomammotropin-h. CS • Relaxin These are secreted into the maternal circulation. Most maternal hormones do not cross the placenta.

Progesterone h. CG Maintains the corpus luteum during h. CS the initial period of pregnancy Maintains the pregnancy Relaxin Oestriol Lactogenic function Growth stimulation Inhibits myometrial contractions 10 6 20 12 30 40 Weeks

Progesterone h. CG h. CS Relaxin 10 6 20 12 Oestriol 30 40 Weeks

Unwanted functions of placenta • Transfer of infectious agents • Transfer of drugs

Functions of the fetal membranes • Protection/shock absorption

Umbilical cord umbilical arteries umbilical vein Wharton’s jelly

References • Review of medical physiology by William F. Ganong • Medical embryology by Jan Langman • http: //www. answers. com/topic/umbilical-cord