Comparative anatomy of the placental barrier.
D000818:Animals; D002823:Chorion / Q000502:physiology; D005260:Female; D006801:Humans; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D011247:Pregnancy; D013499:Surface Properties; D015017:Yolk Sac / Q000502:physiology