Assertion: circulatory system's heart | /r/HasProperty | provided with valve
Facets:
Source sentences:
text: He stated that the heart was a pumping organ provided with valves, to maintain the flow of blood only in one direction; that blood was distributed to the organs by means of deep laying vessels, which he called arteries, and the blood was returned to the heart by more superficial vessels called veins, which still holds true.