By David Richfield (User:Slashme)When using this image in external works, it may be cited as follows:Richfield, David (2014). “Medical gallery of David Richfield”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.009. ISSN 2002-4436. – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2264027

The sarcomere is the contractile unit of skeletal muscle. It contains light and dark bands, with light bands containing thin filaments and dark bands containing thick filaments. The light bands are also known as I-Bands and contain actin, troponin and tropomyosin. Dark bands are also known as A-Bands and contain actin. During contraction the filaments slide past each others, causing a change in the coloration of the striations. The passing of the filaments happens across the H-Zone and the M-Line.