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34 Cards in this Set
- Front
- Back
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______ describes how actin and myosin interact to shorten a muscle and generate force.
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Sliding filament theory
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What muscle tissues are exciteable?
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They all are.
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______ is a myofilament about 15 nm in diameter composed of bundled myosin molecules.
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thick filament
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_____ is a myofilament about 7 nm in diameter composed of actin, troponin, and tropomyosin.
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thin filament
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_____ is a regulatory protein associated with tropomyosin that acts as a calcium receptor (safety on gun)
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troponin
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The myosin head must have a ___ molecule bound to it to initiate the contraction process.
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ATP
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When you run hard and get cramps, you are running out of ___
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ATP
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____ signal for calcium entry
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channels
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_______ stores calcium
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sarcoplasm reticulum
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Rigor mortis is the hardening of the muscles after death b/c they cannot relax b/c ____ is no longer produced after death.
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ATP
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_____ is a light band of only thin filaments
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I band
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_____ has a dark appearance formed by parallel thick filaments that partly overlap the thin filaments
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A band
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____ is a protein to which thin filaments and elastic filaments are anchored at each end of a sarcomere.
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Z disc
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appearance of _______ is a narrow dark line in the middle of the I band
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Z disc
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_____ is the smooth ER of a muscle fiber which is a calcium reservoir
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sarcoplasmic reticulum
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_____ is the plasma membrane of a muscle fiber (sock)
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sarcolemma
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_____ is the cytoplasm of a muscle fiber
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sarcoplasm
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_____ is a bundle of protein myofilaments
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myofibril
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_____ is an extension of the sarcolemma extending from 1 side of the muscle fiber to the other and it conveys electrical signals from the cell surface to its interior
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T tubule
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______ is the dilated ends of sarcoplasmic reticulum adjacent to a T tubule
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terminal cisternae
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_____ makes ATP which you need for contraction
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mitochondria
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What happens to vertebral discs as more force is generated?
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They get closer together.
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A single myosin _____ has a tail that is fixed and a head that flexes.
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filament
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Many myosin filaments fit together to make ________.
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thick filaments.
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Myosin heads bind actin filaments, only if _______ does not cover actin.
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troponin
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_____ is a globular subunit of F actin with an active site for binding a myosin head
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G actin
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Many actins bind with many myosin heads on the thick filaments during a _____.
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contraction
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_____ consist of all the actin and myosin found between 2 Z-lines.
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sarcomeres
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What happens to sarcomeres during a contraction?
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They shorten.
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______ are oranized groups of actin/myosin filaments inside a myofiber.
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myofibrils
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During contraction the opposing Z-lines are drawn closer together by the ______ of the myosin heads along the actin filaments.
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ratcheting action
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Ratcheting of myosin heads across actin _____ the myofiber.
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shortens
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As the sarcomeres shorten, the z-lines (discs) get closer, eventually crunching into _____.
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myosin
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The crunch prevents further shortening and limits the _________.
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maximum contraction (muscle shortening)
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