Assertion: valve | /r/CapableOf | promote unidirectional flow of blood
Facets:
value: toward the heart
type: TRANSITIVE-OBJECT
Source sentences:
text: Because they are low-pressure vessels, larger veins are commonly equipped with valves that promote the unidirectional flow of blood toward the heart and prevent backflow toward the capillaries caused by the inherent low blood pressure in veins as well as the pull of gravity.