Each muscle fiber consists of a cross-banded structure that is further divided into myofibrils that contain thick (myosin) and thin (actin) myofilaments, which give muscle its stripe appearance.

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such as the leg muscles used for jumping, have fewer mitochondria but more myofibrils to generate force. In humans, the muscles are to some extent affected by training. The work is published in ...

Next, the team isolated the heart muscle cells (cardiomyocytes) and fibers within the cells (myofibrils) and looked into how these adapted after a big feeding and compared them with those from starved ...