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13 Cards in this Set
- Front
- Back
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titin
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runs from z line to m line
connects z line to thick filaments, stabalizes |
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nebulin
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each thing filament has one nebulin molec, anchors capping protein and helps set length
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tropomodulin
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actin capping protein of thin filaments, protects em from depolymerization
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Cap Z
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cap at the Z line en, helps anchor thin filament
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myosin molecule
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thick filament dimer, tail(light myosin), hinge (S2) and business end (s1)(heavy myosin)
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what special structures does the head region contain
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an ATPAse and an actin binding domain
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what governs the rate of ATPase activity and therefore the speed of muscle shortening??
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isozymes of myosin only
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tropomyosin (not tropomodulin)
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winds around the actin helix , covers the actin binding sites
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troponin
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a globular protein bound to tropomyosin
has three sites TnI - inhibitory, inhibits activation of myosin ATPase by actin TnT - site of attachment of troponin to tropomyosin TnC - binds Ca Ca binds to troponin C, causing changes in regulatory proteins that then shift tropomyosin out of the way |
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isotonic vs isometric contraction
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isotonic - filaments slide
isometric - minimal sliding but force is produced |
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preload
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length of muscle - number of sites of interaction between thin and thick filaments
amount of force that can be developed, potential force |
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optimal overlap
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have a range of optimal ovelap, due to bare zone in thick filaments where there are no heads so can't make anymore connections and before the thin filaments start to overlap
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Regulation of striated muscle, is it on or off usually?
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A disinhibition system
striated muscle is always ON, but the troponin/tropomyosin system inhibits it Ca comes along and moves the troponin-->tropomyosin causing DISINHIBITION |
