Assertion: epithelium's surface | /r/HasProperty | exposed to the lumen of organs
Facets:
value: to the external environment
type: TRANSITIVE-OBJECT
Source sentences:
text: One layer of cells has an apical surface exposed to the lumen of organs or to the external environment.
text: They have 1 surface that is not attached to any cell, either exposed to the external environment or the lumen of an organ.
text: Similarly, only one layer of cells has the apical surface exposed to the lumen of the organ or to the external environment.