Striated muscle

Our skeletal muscles, those over which we have conscious control, are made up of fine fibres. Under the microscope the fibres have a distinct striated appearance with cross bands of different thickness. The muscle fibres are packed with myofibrils which are are cylindrical arrangements of myofilaments, made up of contractile proteins called actin and myosin, the arrangement of which create the light and dark banded appearance of a muscle fibre. These myosin and actin filaments slide across each other, causing the muscle to contract.