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Ch11 Musclar tissue1
microscopic anatomy of skeletal muscle
Question | Answer |
---|---|
sarcoplasmic reticulum | a reservoir of calcium ions; it has gated channels in its membranes that allow a flood of calcium ion into the cytosol where it activates muscle contraction. |
A T tubule and its associated two terminal cisternae constitute a | triad |
contractile proteins | Myosin and actin are called contractile proteins because they accomplish the shortening of the muscle fiber |
regulatory proteins | Tropomyosin and troponin are called regulatory proteins because they act like a switch to determine when the fiber can contract or not contract |
The action of these regulatory proteins depends on the availability of ___________, which bind to troponin. | calcium ions |
Dystrophin | an enormous protein located between the sarcolemma and the outermost myofilaments; it links actin filaments to a peripheral protein on the inner face of the sarcolemma. |
A band | Dark bands that consist of thick filaments lying side by side that partly overlap the thin filaments |
H band | the lighter area is the A band contains thick filaments only |
M line | dark band in center of an H band, where myosin bands connect |
I band | light band consists of thin filaments only but isbisected by a dark narrow Z disc (Z line) |
Z disc (Z line) | which provides anchorage for the thin filaments and elastic filaments. |