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32 Cards in this Set
- Front
- Back
name the three types of muscle fibers?
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skeletal, cardiac, and smooth
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name the parts of the skeletal muscle from outter to inner
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sarcolemma, sarcoplasm, myofibrils, and filaments
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what are the thick filaments composed of?
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myosin
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what are the thin filaments composed of?
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actin
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acronym for the sarcomere
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haiz- h-zone,a-band, i-band, z-disc
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which part of the sarcomere does not shorten when the muscle is contracted?
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A band
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what do myosin heads act as?
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myosin ATPase, splitting ATP into ADP and Pi
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what are actin tin filaments composed of?
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two intertwined helical chains
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where are troponin and tropomyosin located?
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actin
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what are cross bridges?
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binding sites between actin and myosin
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describe the cross bridge formation
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1) resting fiber, cross bridge is not attached to actin
2) cross bridge binds to actin 3) Pi is released, causing conformational change in myosin 4) power stroke causes filaments to slide; ADP is released 5) a new ATP binds to myosin head, allowing it to release from actin 6)ATP is is hydrolyzed causing to return to its original orientation |
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what causes the sliding of the filaments and muscle contraction?
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the cross bridge cycle
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The transverse tubules contain voltage gated Ca++ channels, called ___________ receptors
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DHP (dihydropyriding)
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direct molecular coupling between what two receptors causes Ca++ channels to open?
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DHP and ryanodine
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what re graded concentration produced by?
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variations in the number of motor units activated
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does fine control or power control have have neuron activated fibers
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power
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name the three stages of a single muscle twitch
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latent, contraction, relxation
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what is complete tetanus
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when a muscle remains contracted due to continues stimulus, results in fatigue
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describe a eccentric contraction
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muscle lengthens due to increased load/tension. coming down from a curl
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what kind of relationship is there between "force of opposing muscle contraction" and " velocity of muscle"
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inverse
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what is the strength of a muscles contraction influenced by?
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1. number of fibers within muscle that are stimulated to contract
2. frquency of stimulation 3. thickness of each muscle fiber (thicker=more power) 4. initial length of muscle fibers when at rest (max 2-2.2) |
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a muscle is made to contract _______________ and the force required to prevent it from shortening is measured as ________ _________
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isometrically; tension produced
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what must be stretched first before the muscle contracts
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tendon
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what do each intensites of excercise burn
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light: fatty acid
moderate: fatty acids and glucose heavy: lots of glucose |
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what increases GLUT4 carriers in sarcolemma?
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muscle contraction
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at what level of exercise has the most ATP production
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moderate
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in exercise intensity increase beyond about 70% of maximal oxygen uptake then ___________ contributes as increased proportion of total ATP
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glycolysis
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what is phosphocreatine and what is it used for?
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reserve of high-energy phosphate in muscle that is used for rapid formation of ATP at beginning of muscle contraction because pre-formed ATP in muscle at start of contraction only supports a few twitches
3x as much as ATP |
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in what three ways can muscle fibers form ATP?
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1.phosphorylation of ADP by posphocreatine (creatine phosphate)
2. oxidative phosphorylation in the mitochondria (aerobic) 3. glycolysis in the cytosol (anaerobic) |
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how are fibes classified?
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the maximal velocity of shortening and the major pathway used to form ATP
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describe oxidative fibers
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-red
-high capacity for oxidative phosphorylation -many mitochondria -good blood supply: O2 and nutrients -high concentrayion of myoglobin |
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describe glycolytic fibers
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-white
-fewer miochondira and blood vessels and less myoglobin -larger diameters and greater tension |