The sliding filament model

• Actin and myosin filaments are arranged in a way they create dark and light bands along the myofibril
• The darker band is called the A band it contains both myosin and actin
• The lighter band is called the I band and it only contains Actin
• Z lines are used to show a small portion of the myofibril → a sarcomere
• Cross bridges → myosin filaments that have tiny projections that extend towards the actin
• During contraction the actin and myosin interlock via the cross bridge and slide over one another so that they myofibril becomes shorter and the length of the muscle decreases