In a healthy heart, microscopic lattice-like structures called myofilaments cause heart muscle cells to contract. The cells work in concert to make the heart contract and relax with each beat.

THE myosin molecule is a slender rod about 1550 Å long and 20 Å in diameter with a globular thickening at one end1–5. Huxley has shown2 that these molecules can combine in vitro to form rod ...

These fibres contain protein filaments, called thick and thin myofilaments, which slide against each other when a muscle contracts. Contraction In a relaxed muscle, thick and thin myofilaments ...