Assertion: vein's valve | /r/HasProperty | closed
Facets:
value: by backflowing blood
type: MANNER
value: normally
type: DEGREE
Source sentences:
text: The most common such abnormality is patent foramen ovale, occurring in about 25% of the adult population, but here the defect functions as a valve which is normally closed, because pressure is slightly higher in the left side of the heart.
text: Valves distal to the contracting muscles are closed by backflowing blood.