Now, remember those tiny myofibrils that bundle up to form your muscle fibers?

现在，还记得那些微小的原捆绑形成你的？

Thousands of tiny, parallel threads called myofibrils squish together to form muscle fibers, which are your actual muscle cells — cells with mitochondria, multiple nuclei, and a cellular membrane called a sarcolemma.

数以千计被称为原的微小平行线挤压在一起形成，这就是你真正的细胞——具有线粒体、多个细胞核和称为膜的细胞膜的细胞。