The stage in human or animal development following
cleavage. During embryonic development the tissues and organs are being built.
When the embryo takes human or animal form, it is known as a fetus. The process
in which tissues are formed is known as differentiation.
Differentiation of the
Three Primary Germ Layers
Ectoderm
Endoderm Mesoderm
skin
lining of lungs muscles
nervous system lining of
skeleton
digestive system sense organs
pancreas
heart
liver blood vessels
respiratory
blood
system
ovaries,
testes
kidneys
