KINE 2011 Study Guide - Endoplasmic Reticulum, Skeletal Muscle, Crossbridge

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Document Summary

Muscle contraction: when muscles develop tension and shorten. Muscle is the largest group of tissue in our body: make up about 50% of our body mass; 40% made up by skeletal muscle alone (mechanical and involved in homeostasis) Striated muscle: cardiac muscle (involuntary, skeletal muscle (voluntary) Striated muscle under a microscope alternating light bands perpendicular to the long axis: seen in cardiac and skeletal muscle. A myofibre is formed by the fusion of undifferentiated and mononucleated cells called myoblasts: myoblast = one single cylindrical, relatively large and elongated, multinucleated cell. In adults 20-100um diameter, 20 cm length. Satellite cells can be used in cases of muscle injury: new fibres can form from these undifferentiated cells. Muscle: a number of muscle fibres bound together by connective tissue: bound to bone by bundles of collagen fibres (tendons) Why we called them striated muscles: they have an arrangement of numerous thin and thick filaments.