[thin layers of tissue which surround the embryo or fetus and provide for its nutrition, respiration, excretion and protection; they form from the egg but are not part of the embryo itself; include the yolk sac, allantois, amnion, and chorion. ( CSP )]
UMLS (CSP) C0935447 Relation/PAR: embryo/fetus
Relation/CHD: amnion
trophoblast
vitelline membrane
vitelline sac
CAM