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64 Cards in this Set
- Front
- Back
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tendon
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an attachment between muscle and bone matrix
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endomysium
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connective tissue around muscle cells
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perimysium
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connective tissue around muscle fascicles; roast beef can easily be torn up by these
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epimysium
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connective tissue surrounding entire muscle
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collagen
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extensible and elastic protein found in muscle connective tissue
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sarcolemma
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plasma membrane of muscle fiber
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sarcoplasm
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cytoplasm of muscle fiber
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myofibrils
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long protein bundles that occupy the main portion of the sarcoplasm
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glycogen
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protein stored in abundance to provide energy with heightened exercise
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myoglobin
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red pigment that stores oxygen needed for muscle activity
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fibrosis
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method of muscle "repair;" nonfunctional tissue replaces muscle
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sarcoplasmic reticulum
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smooth ER that forms a network around each myofibril; acts as a CALCIUM RESERVOIR
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terminal cisternae
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dilated end-sacs of SR that cross muscle fiber from one side to another
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T tubules
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transverse tubules; tubular infoldings of sarcolemma which penetrate through the cell and emerge on the other side
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triad
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2 terminal cisternae w/ a T tubule in the middle
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thick myofilaments
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2 chains of myosine intertwined to form shaft-like tail; has golf-club heads
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thin myofilaments
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1. Fibrous (F) actin is composed of two intertwined strands of globular actin that has an active site for myosin heads.
2. Tropomyosine: protein that blocks active sites 3. Troponin: calcium, ATP, and tropomyosine bonding protein on each tropomyosine; need Ca to change conformation |
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titin
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connectin; a huge springy protein that keeps myosin and actin attached; prevents over stretching, flank each thick filament to the Z disc
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regulatory proteins
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Troponin and tropomyosine
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contractile proteins
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actin and myosine
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dystrophin
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accessory protein associated w/ actin; links filaments to transmembrane proteins and endomysium; TRANSFERS FORCE OF MUSCLE CONTRACTION TO CONNECTIVE TISSUE AROUND MUSCLE CELL
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sarcomere
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basic contractile unit of muscle fiber; from 1 z disc to another
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contraction
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Z discs move closer together; thick/thin filaments do not shorten, but overlap
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somatic motor neurons
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nerve cells whose cell bodies are in the brainstem and spinal cord that serve skeletal muscles
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somatic motor fibers
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AXONS of somatic motor neurons that lead to skeletal muscle; each nerve fiber branches to many muscle fibers, but each muscle fiber is supplied by only one motor nueron
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motor unit
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one nerve fiber and all the muscle fibers innervated by it
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NMJ
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neuromuscular junction; where nerve fiber meets muscle fiber
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curare
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molecule that completes with Achytlcholine for receptor sites but does not stimulate muscle--causes flacid paralysis
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depolarization
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cell membrane becomes briefly positive when Na ions rush in
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repolarization
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cell membrane becomes negative again when K slowly diffuses out of cell
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action potential
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quick up and down voltage shift from negative RMP to positive value, then back to negative
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EPP
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end plate potential, caused by quick shifts in charge due to Na and K moving
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rigor mortis
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muscles harden and stiffen after death: body can no longer produce ATP so myosine heads cannot release
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muscle tone
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state of slight partial contraction of muscle maintained by central nervous system for good contractions--maintains OPTIMUM RESTING LENGTH
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threshold
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minimum voltage necessary to generate an action potential and produce a contraction
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latent period
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2 msec delay b/w onset of stimulus and onset of twitch response---force generated during this period is called internal tension
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recruitment
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multiple motor unit, nervous system brings more motor units into play for a stronger contraction
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treppe
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(assuming voltage is constant) muscle recovers b/w twitches but each twitch develops more tension then the next
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incomplete tetanus
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new stimulus arrives before the other is over and "ride piggyback" on the former
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temporal summation
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results from two stimuli arriving close together
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wave summation
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when one wave of contraction is added to another
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complete tetanus
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muscle has NO TIME to relax between contractions, results in one smooth, long, contraction (4x tension of normal twitch)
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isometric contraction
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occurs when muscle produces internal tension while external resistance causes it to stay the same length/become longer (pushing against wall)
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isotonic contraction
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muscle changes in length with no change in tension
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concentric contraction
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muscle shortens while maintaining tension (flexion)
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eccentric contraction
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muscle lengthens as it maintains tension
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two main pathways of ATP synthesis
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1. Anaerobic fermentation (glycolysis): fast, but little atp
2. Aerobic fermentation: requires continual supply of oxygen but makes 36 ATP |
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modes of ATP synthesis during exercise
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Aer planes go away.
1. Aerobic resp using oxygen from myoglobin (10 seconds) 2. phosphagen system (transfers form myokinase and creatine) (6 seconds) 3. Glycogen-lactic acid system (aNAEROBIC FERMENTATION) 4. Aerobic resp, supported by cardiopulmonary function |
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Glycogen-lactic acid system
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anaerobic fermentation
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phosphagen system
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VERY SHORT energy supply, but supplies short bursts of energy by borrowing phosphate groups from myokinase and creatine, adding to ADP to make ATP
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maximum oxygen uptake
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point at which theh rate of oxygen consumptions reaches a plateau and does not increase w/ added workload; can result in 2x ATP production!
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EPOC
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repaying oxygen debt, Excess post-exercise oxygen consumption
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Type 1 Fibers
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SO fibers, slow twitch/slow oxidative fibers. Red w/ abundant capillaries, are fatigue resistant, and "trained" for aerobic respiration
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Type 2 Fibers
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FG, fast twitch/fast glycolyctic fibers, fibers are well-adapted for quick bursts of energy (anaerobic ferm) fatigues quickly due to lactic acid created
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intercalated disc
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gap junctions that allow a cardiac muscle cell to instantly alert its neighbor to contract
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autorhythmic
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heart muscle is autorhythmic because it does not require a nerve signal to contract, has a built-in pacemaker that rhythimicaly sends out a wave of electrical excitation
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smooth muscle
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1. fusiform shape
2. no striations 3. no z discs - instead DENSE BODIES 4. No T tubules: calcium comes from ECF 5. regenerates will 6. can undergo mitosis 7. can contract without nervous stim |
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multiunit smooth muscle
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autonomic innervation, irises of eye, piloerectors, sim. to skeletal muscle, each motor unit contracts independently
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single unit smooth muscle
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VISCERAL MUSCLE, more widespread than multiunit smooth muscle, blood vessels, respiratory/digestive/urinary tracts, connected by GAP junctions are contract as a single unit
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stimulation of smooth muscle
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2 nuerotransmitters
1. achytylecholine and 2. norepinephrine |
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variscosities
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bead like sweelings on autonomic smooth muscle nerve fibers
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calmodulin
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protein on thin filaments that calcium bonds to in smooth muscle INSTEAD of troponin (in skeletal)
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latch-bridge mechanism
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resistant to fatigue, method of smooth muscle contraction
slow, myosin heads don't release immediately, therefore don't use up more ATP by letting go, save ATP |
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plasticity
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ability of smooth muscle to adjust its tension to the degree of stretch, as in bladder
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