When the heart contracts, that papillary muscle keeps the chordae tendineae taut; and both of these help to prevent regurgitation of blood back into the atrium, allowing it to only flow out the next valve.

当心脏收缩时，乳头肌使腱索绷紧；两者有助于防止血液反流到心房，使血液只能从下一个瓣膜流出。