Assertion: alveolus | /r/LocatedNear | capillary network
Facets:
Source sentences:
text: This function is further increased by the fact that each alveolus is surrounded by a capillary network so extensive that it forms an almost continuous sheet of blood around each alveolus.
text: One alveolus is a singular, tiny air sac of the lung, surrounded by a network of capillaries, and through which oxygen and carbon dioxide are exchanged.