The m line
Actin
It is a section of the Sarcomere that stretches from one end of the Myosin filament to the other, and also includes parts of the Actin filaments that overlaps it.
The length of the thick filament is the A band. The A band contains both thick and thin filament because they are overlapping each other. The H band is thick filament only, however, it only covers a portion of width of the thick filament.
The sliding filament theory is the explanation for how muscles produce force (or, usually, shorten). It explains that the thick and thin filaments within the sarcomere slide past one another, shortening the entire length of the sarcomere. In order to slide past one another, the myosin heads will interact with the actin filaments and, using ATP, bend to pull past the actin.
The filament is made of tungten and these 'wires' (filament) conduct electricity.
The three sections along the length of a sarcomere are the A band, the I band, and the H zone. The A band is the dark region in the center of the sarcomere that contains both thick and thin filaments, while the I band is the light region at the ends of the sarcomere that contains thin filaments only. The H zone is the region in the center of the sarcomere where only thick filaments are present.
Sarcomeres are composed of actin (thin filaments) and myosin (thick filaments).
The sarcomere itself will become shorter.The sarcomere will shorten.
Sarcomere
Electrical filament
A sarcomere consists of thin and thick filaments arranged so they can slide over each other. The boundary of the sarcomere are the Z lines. Thin filaments extend from the Z lines and overlap with thick filaments in the middle of the sarcomere. The I band is on each side of the Z line where only thin filaments occur. The A band is the length of the thick filaments and is divided into three parts; the zone of overlap is on each end where thin and thick filaments occur, the H band is in the middle and has only thick filaments, and the M line is the center of the A band.
That is the filament. Electricity traveling through the filament heats it to the point of glowing brightly - that is the light bulbs "light".