BIO 203 Lecture Notes - Lecture 13: Cartilage, Golgi Tendon Organ, Chitin
17 Dec 2016
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Document Summary
Skeletal muscle fibers are large multinucleus cells that appear striped or striated under the microscope. Bundled into fascicles surrounded by connective tissues: fibers internal structures. Network of transverse tubules: t tubules connected with the sarcolemma: myofibrils are the contractile strutures. Cardiac muscle fibers are also striated but they are smaller, branched, and uninucleated. Cells are joined in series by junctions are called intercalated disks. Smooth muscle fibers are small and lack striations. I band is made of thin filaments only (actin) Light and dark bands seen under light microscopy. One sarcomere between by 2 z disks. A band is made of darker regions where both light and heavy filaments overlap. H zone is a clear band in the middle of the a band, heavy filaments only. M line represents the proteins to which heavy filaments attach. The sarcomere shortens during contraction: as contraction takes place, actin and myosin do not change length but instead slide past each other.
