Assertion: epithelium's layer | /r/MadeOf | no blood vessels
Facets:
Source sentences:
text: Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane.
text: Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane.