How Is The Human Muscle Organized?

the muscle is made up of types of fibres, actin fibres and myosin fibres. the actin are the thin type and the myosin are the thick type. muscle contractions work by the binding of myosin heads attaching onto the actin binding sites and once attached the myosin heads ‘cock’ which causes the actin to slide across pulling them inwards so the muscle shortens. these movements are very very tiny but because of the number of movement going on at one time the sizes all add up. the binding of the myoson is all down to ATP where ADP and iPhosphate are rejoined to store energy to ATP and then broken back to release energy when the myosin joins onto the actin binding sites. the binding sites are covered normally because tropomyosin is wrapped around the actin but troponin bind the the tropomyosin and cause it to distrort and ‘shift’ along the actin fibres so the binding sites are exposed. there are many websites that will go into more detail as this is all off the top of my head from memory, just search muscle fibres or how mucsles contract?there are also illustrations showing how the muscle is structured. hope this helps