Development of the Placenta and fetal membranes - Learning Objectives F'22

Development of the Placenta; Twinning and Parturition Learning Objectives  Read: Chapter 5; pp45-47 Chapter 8; pp71-89 The placenta is the primary site of nutrient and gas exchange between the mother and the fetus. The placenta is a fetomaternal organ composed of fetal chorionic plate and chorionic villi (formed by trophoblast and extraembryonic mesoderm) and part of the maternal endometrium: the decidua basalis (decidual plate).  Describe the maternal functional endometrium(decidua): decidua basalis, decidua capsularis and decidua parietalis.  Describe the formation of the primary chorionic villi (fig 4-4).  Describe how the primary chorionic villi mature to form the secondary and tertiary chorionic villi (What are the key components distinguishing primary, secondary, and tertiary chorionic villi?) (fig 5-11).  Describe the outer cytotrophoblast shell and the intervillous spaces.  Distinguish the rough and smooth chorion (chorion frondosum and chorion leave)  Describe the placental membrane (barrier).  Describe placental circulation (fetoplacental and maternal-placental) on pp 74-75 and figure 8-5. Do the fetus and mother exchange blood cells? Describe the placental membrane (barrier).  Trace the flow of nutrients and oxygen from the mother’s circulation to the embryo circulation and metabolic wastes and carbon dioxide from the embryo back to the mother’s blood. (fig. 8-7) Relate this to how nutrients and toxins in mother’s blood may affect the developing fetus.  What substances can cross the placental membrane? What microorganisms? What advice you would give a pregnant client based on the information in figure 8-7?  Describe the functions of the placenta and umbilical cord.  Outline and/or draw the components that make up the placenta (decidua basalis & villous chorion) and know which one is from the mother and which is from the fetus (fig 8-1).  Describe the formation of the amniochorionic membrane by the fusion of the chorionic and amnion as the fetus grows and obliterates the chorionic cavity (figs. 8-1, 8-3).  Explain what happens to the placenta and amniochorionic membrane during and after birth.  Describe abnormalities of placenta: placenta acreta, placenta percreta and placenta previa. Twinning and Childbirth (parturition)  Describe the difference between dizygotic(fraternal) and monozygotic (identical) twins.  Describe the stages of labor: dilation, expulsion, placental separation  Describe the difference between the fetal surface (amnion covered chorionic plate) of the delivered placenta compared to the endometrial surface (side demonstrating fetal cotyledons and sloughed endometrial tissue) of the delivered placenta.  Describe the functions of amniotic fluid.  Describe disorders of amniotic fluid volumes (oligohydramnios and polyhydramnios. Looking forward into Winter and Spring quarter: