reflexive contraction

例句：

1. 1. When the muscles are relaxed, they undergo a reflexive contraction that helps to maintain posture.
   肌肉放松时，它们会经历一种反射性收缩，有助于维持姿势。
2. 2. This process is often referred to as reflexive contraction, which occurs when the body senses danger and responds with an automatic contraction of muscles.
   这个过程通常被称为反射性收缩，当身体感知到危险并自动收缩肌肉时发生。
3. 3. In this case, the reflexive contraction of the heart muscle is crucial for maintaining blood pressure andoxygen supply to the brain.
   在这种情况下，心脏肌肉的反射性收缩对于维持血压和向大脑输送氧气至关重要。