Uberon definition : Tertiary chorionic villi contain embryonic blood vessels that develop from mesenchymal
cells in the loose connective tissue core. These blood vessels connect up with vessels
that develop in the chorion and connecting stalk and begin to circulate embryonic
blood about the third week of development in humans.;
Tertiary chorionic villi contain embryonic blood vessels that develop from mesenchymal
cells in the loose connective tissue core. These blood vessels connect up with vessels
that develop in the chorion and connecting stalk and begin to circulate embryonic
blood about the third week of development in humans.