Biology 2290F/G Lecture 1: Stavraky Notes
14 Dec 2017
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Document Summary
Muscle fassicles muscle cells (fibers) myofibrils myofilaments (thick and thin) Muscle cells contain glycogen and lipids for energy and myoglobin to store oxygen. Muscle cells: cylindrical, multi-nucleated, striated (sarcomeres), multi-mitochondria, length varies from a few mm to 12 cm. Sarcoplasmic reticulum: sleeve like structure around each myofibril with lateral sac (terminal cisternae) at ends to store ca++ and release it during muscle contraction. Traverse tubules: continuous with the cell membrane wrap around myofibril, transferring ap and ca++ inside the cell to the myofilaments. The sarcoplasmic reticulum does not come into contact with the t- tubule; the lateral sac of the sr is next to it but not directly in contact with it. A globular protein forming a two-stranded chain. A rod shaped protein that lies in the grooves formed by actin molecules. In the relaxed muscle, tropomyosin is situated such that it partially covers the myosin binding sites on the actin: troponin.
