The ___ is a ___ structure composed of ___ ( ____ ) and ___ membrane tissues, where the ___ and ___ blood circulations are brought very close together over a ___ surface area, but do not mix.
placenta | disc-shaped | maternal | endometrial | fetal | maternal | fetal | huge
placenta | cone | maternal | endometrial | fetal | paternal | fetal | tiny
placenta | disc-shaped | paternal | endometrial | embryonic | maternal | fetal | large
placenta | oval | maternal | endometrial | fetal | maternal | fetal | small
___ and ___ are connected by ___ and a ___ in the ___. Exchange in the placenta takes place via ___ and ___.
Placenta | fetus | arteries | vein | umbilical cord | diffusion | active transport
Umbilical cord | fetus | arteries | vein | placenta | diffusion | active transport
Placenta | fetus | arteries | vein | umbilical cord | diffusion | bulk transport
Placenta | embryo | arteries | vein | umbilical cord | diffusion | active transport
Movements across the placenta involve :
oxygen & carbon dioxide
water & glucose
antibodies & amino acids
urea & ions & glucose
urea & glucose & blood
oxygen & carbon monoxide
antibodies & viruses
amino acids & starch
ions & electrons & phospholipids
water & maternal waste products
The placenta is ___ bacteria, although ___.
a barrier to | some viruses can cross it
a pathway for bacteria | no pathogens can live in it
a barrier to | most viruses can cross it
a barrier to | all viruses spread trying to cross it