ChorionDevelops a rich supply of blood vessels and forms an intimate association with the endometrium (lining) of the female’s uterus. Chorion and endometrium together form the placentaplacenta Amniotic sac A membrane sac begins to fill with fluid. It is the inner membrane of the chorion. Amniotic fluid A pale yellow fluid that serves to cushion the unborn baby from jolts and bumps. It provides a stable temperature and assists in maintaining a consistent body temperature. The fluid allows the baby to move freely and exercise growing muscles to develop a symmetrical musculoskeletal system. It allows for lung development as the baby begins to breathe amniotic fluid to strengthen his lungs and swallow fluid to develop the gastrointestinal tract. The kidneys develop as the baby urinates in the fluid. Umbilical cord Nutrients and oxygen move from the mother’s blood into the placenta, through the umbilical cord, and then to the fetus. Wastes are the fetus move through the umbilical cord, to the placenta, and then into the mother’s blood Quick Vocabulary

Think, Pair, Write: What do you notice? Write about the placenta, the chorion and the amniotic sac LEFT

Do identical twins always share a placenta during pregnancy? No, this is a myth. Even many doctors will mistakenly identify twins as fraternal because there are two placentas. It depends on when the egg splits. If it is early enough, the two embryos will implant separately in the uterus and develop individual placentas. If the split occurs later, they may share a placenta.

Think, Pair, Write: What do you notice? Write about the umbilical cord. LEFT Use your book, pg 518 – 520: Create two lists: 1)Important things for fetal growth 2)Things that are bad for fetal growth The placenta contains many blood vessels from both the fetus and the mother, but they are NOT directly connected.

Quick quiz – what do all these mean?

Stomach vs. Uterus Think, Pair, Write: What do you notice? Write about the differences in location and function of the stomach and the uterus. LEFT

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