[HD 1004] - Final Exam Guide - Everything you need to know! (76 pages long)
Document Summary
Support for the embryo. (3) implantation takes place about 10 days after conception with the attachment of the zygote to the uterine wall: the second stage of prenatal development is the embryonic period and it lasts from about. The developing organism is now called the embryo: during this phase, cell differentiation intensifies and some cells form support systems while others develop into organs. These include the following: (1) the amnion is a fluid-filled bag in which the embryo floats. (2) umbilical cord: the umbilical cord contains two arteries and one vein that connect the embryo to the placenta. Small-molecule materials, such as oxygen, water, salt, carbon dioxide, and nutrients can cross back and forth between mother and infant. The fetus shows a preference for a certain position in womb: by the end of the 6th month, eyes and lids have formed, fine hair covers the head, and the grasp reflex is present.
