Umbilical cord from and contains remnants of the yolk sac and allantois. It forms by the fifth week of development, replacing the yolk sac as the source of nutrients for the embryo. The cord is not directly connected to the mother's circulatory system, but instead joins the placenta, which transfers materials to and from the maternal blood without allowing direct mixing. The length of the umbilical cord is approximately equal to the crown-rump length of the fetus throughout pregnancy. The umbilical cord in a full term neonate is usually about 50 centimeters (20 in) long and about 2 centimeters (0.75 in) in
The Cord and the Ax The Cord and the Ax "The Cord and the Ax" is the third episode of the second season of the American science fiction series Defiance, and the series' fifteenth episode overall. It was aired on July 3, 2014. The episode was written by Allison Miller and directed by Michael Nankin. Stahma (Jaime Murray) and Alak (Jesse Rath) are invited to Rafe's (Graham Greene) house for a family dinner where Christie (Nicole Muñoz) wants to announce that she is pregnant but the surprise is ruined because Stahma can smell it. Everyone is really happy with the news and Rafe, after the