Assertion: lymphatic system's vessel | /r/HasProperty | covered by smooth muscle cells
Facets:
Source sentences:
text: To do so, the collecting vessels contain intraluminal valves to prevent backflow and are covered by smooth muscle cells, which periodically contract to drive lymph forward.
text: To do so, the collecting vessels contain intraluminal valves to prevent backflow and are covered by smooth muscle cells, which periodically contract to drive lymph forward.