Events of Embryonic
Development
•
Formation & Roles of
embryonic
membranes
§
Amnion
§
Yolk sac
§
Allantois
•
Germ layers
§
Ectoderm (outer)
§
Endoderm (inner)
§
Mesoderm (middle)
1.
Embryonic membranes
1.
Provides watery environment that protects the embryo
2.
Forms part of the gut, produces earliest blood cells.
Source of germ cells that form gonads
3.
Forms umbilical cord and forms part of the bladder.
2.
Germ layers
1.
Forms nervous system, skin epithelium
2.
Forms inner layers of digestive, epithelial, and urogenital systems
3.
Forms everything else.
