Other
Temple University Med School: Ventricular System Development (Early)
Upper-level explanation of early human ventricular system development. Provides interactive labeled diagrams and description of weeks 4, 5, and 6 in embryo development.
CK-12 Foundation
Ck 12: Life Science: 11.72 Pregnancy
Understand fetal growth during pregnancy in humans.
Other
Story md.com: Conception to Birth
See the amazing process of human conception followed by the development of the embryo through each week of the pregnancy to the birth.
Khan Academy
Khan Academy: Human Embryogenesis
Explains what happens during embryogenesis, the first eight weeks of pregnancy.
University of Michigan
University of Michigan/human Embryonic Stages
Sample images of Carnegie stages of human embryo throught the first trimester.
Exploratorium
Exploratorium: Cual Embrion Es Humano?
An exhibit that explains why the embryos of vertebrates look so much alike.