Assertion: vein | /r/HasAspect | valve
Facets:
value: to prevent blood
type: PURPOSE
value: in them
type: LOCATION
value: into their lumens
type: LOCATION
Source sentences:
text: The tunica intima differs from the inner layer of an artery: many veins, particularly in the arms and legs, have valves to prevent backflow of blood, and the elastic membrane lining the artery is absent in the vein, which consists primarily of endothelium and scant connective tissue.
text: Veins differ from arteries in that veins may have valves that project into their lumens to prevent the backflow of blood, they have larger lumens, and they have less smooth muscle.
text: Some veins, particularly veins in the legs, have valves in them, to prevent blood from flowing backward.
text: Some veins, particularly veins in the legs, have valves in them, to prevent blood from flowing backward.
text: Pressure diminishes at the ends of capillary beds, so veins have valves to prevent backflow.
text: Many veins, especially those in the limbs, have valves, formed from folds of the tunica intimathat prevent the backflow of blood.
text: In addition, veins are structurally different than arteries in that veins have valves to prevent the backflow of blood.
text: Many veins have valves to prevent back flow of blood, whereas venules do not.