Assertion: lymphatic system's heart | /r/HasProperty | pump
Facets:
value: to maintain the flow of blood
type: PURPOSE
Source sentences:
text: The heart is a pump made of cardiac cells that circulates blood and lymph throughout the body.
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.