Need an overview of the following topics:
- Extraembryonic membranes and placentation
- Digestive system
- Development of nervous system
Here's a great picture of the extraembryonic tissues http://18.104.22.168/faculty/webpages/stodd/oceanweb/bio2/bio2lectures/Lecture9/sld031.htm and http://ulisse.cas.psu.edu/4hembryo/physiology.html
These tissues form from the dividing blastoderm but do not contribute to the embryo proper. Instead they provide vital support and protection to the embryo. The extraembryonic tissues consist of the yolk (provides lipid rich nutrients ie food), allantois (collects waste products, allows for gas exchange and digestion), chorion (protects the embryo by emclosing it and the other etra-embryonic tissues) and amnion (protective cushion that allows for embryonic movement).
The placenta is a specialized structure found in mammals. It is the primary connection between teh embryo and its mother. Unlike in egg laying animals, mammalian embryos receive their oxygen and nutrients through the placenta. The flow of blood returning to the mother provides filtration of waste by the mother's kidneys. For more detail see ...
Embryology terms such as extraembryonic membranes and placentation, digestive system, and Development of Nervous system are reviewed.