FOETAL EMBRYOLOGY

SYSTEMIC EMBRYOLOGY

X XX XX XX XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX ~~~~ - ZYGOTE - TWO CELLED STAGE - FOUR CELLED STAGE - EIGHT CELLED STAGE - SIXTEEN CELLED STAGE - FLUID ENTERS BETWEEN CELLS TT EEEE - FLUID ENTERS BETWEEN CELLS , E = inner cell mass (Embryoblast) , T = Trophoblast , ~ = Blastocoel ( Blastocyst cavity) EEEE EEEE EEEE ~~~~ TT EEEE - FLUID ENTERS BETWEEN CELLS , E = inner cell mass (Embryoblast) , T = Trophoblast , ~ = Blastocoel ( Blastocyst cavity) EEEE - TT = embryonic pole , tt = Abembryonic pole EEEE EEEE ~~~~ tt TT CCCC - FLUID ENTERS BETWEEN CELLS , E = inner cell mass (Embryoblast) , T = Trophoblast , ~ = Blastocoel ( Blastocyst cavity) DDDD - TT = embryonic pole , tt = Abembryonic pole - C = Ectoderm , D = Endoderm ~~~~ tt TT AAAAAAA A~A~A~A~A~ - A~ = amniotic cavity , Y~ = yolk sac or primary yolk sac CCCCCCCC DDDDDDDD Y~Y~Y~Y~Y~ HHHHHHH