1.Both of these have chordae tendineae coming off of them that tether the valve to the papillary muscles in the left ventricle.

这两种都有腱索，连接到左心室的乳头肌上。

2.And each cusp looks kind of like a parachute, because it has tiny little strings, called chordae tendineae, coming off of it that tether the cusps to a small muscle called the papillary muscle.

每个尖瓣看起来就一个降落伞，因为它有的弦，叫腱索；腱索将尖瓣连接在一块叫做乳头肌的肌肉上。

3.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。