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106 Cards in this Set
- Front
- Back
Muscles transform Chemical Energy (ATP) into...
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Directed Mechanical Enery
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Excitability
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The ability to receive and respond to a stimulus
(stimulus is usually a chemical) |
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Contractility
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The ability to shorten forcibly when stimulated- this sets muscle apart from all other tissues
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Extensibility
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ability to be stretched or extended
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Elasticity
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the ability of a muscle fiber to recoil and resume length after being stretched
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Functional Characteristics of muscle tissue
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Excitability, contractility, extensibility, elasticity
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Muscle Functions/Properties of Homeostasis
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Produce movement, maintain posture, stabilize joints, generate heat
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Thick filaments contain
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bundled myosin molecules
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thin filaments contain
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actin molecules
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elastic filaments do this
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maintain the organization of the A band
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muscle metabolic waste is removed by
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veins
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each muscle fiber is surrounded by
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endomysium
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easch fascicle is surrounded by
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perimysium
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the entire muscle is surrounded by
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epimysium
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what joins muscles to bones?
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tendons
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series elastic components are...
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connective tissue sheaths
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indirect attachments are more common why?
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durability
small size cross rough bony projections can pass over a joint conserve space |
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the plasma membrane of a muscle cell
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sarcolemma
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I band contains
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thin filaments only
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H zone contains
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thick filaments only
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M line contains
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thick filaments linked by accessory proteins
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outer edge of A band contains
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thick and thin filaments overlap
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cytoplasm of muscular fiber
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sarcoplasm
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sarcoplasm contains glycosomes which are
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granules of stored glycogen
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myoglobin is
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red pigment that stores oxygen
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functional unit of skeletal muscle
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sarcomere
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this links the think and thick filaments together
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globular heads
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what splits atp?
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ATPase enzymes
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What does tropomysosin do?
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reinforces actin filaments
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when tropomyosin is relaxed, does mysoin bind?
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NO
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Elastin is composed of
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Titin
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2 functions of Titin (elastic filament)
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holds hick filaments in place
assists the muscle cell to spring back into shape |
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as titin uncoils, it does this
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stiffens which helps excessive stretching
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dystrophin does this
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links think filaments to intergral proteins of the sarcolemma
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Major role of sarcoplasmic reticulum
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regulate intracellular levels of ionic calcium
stores calcium and releases it on demand |
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A triad is composed of
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a t-tubule and 2 terminal cisternae
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sliding filament theory of contraction states
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thin filaments slide past thick ones so that actin and myosin filaments overlap
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during contraction, what happens to the H zones?
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they disappear
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symptoms of myasthenia gravis include...
(and what is is caused by?) |
drooping eyelids, difficulty swallowing and talking, muscle weakness.
caused by shortage of Ach receptors |
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the sarcolemma is negative, which means it is...
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polarized
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why is the contraction phase longer than the AP itself?
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active transport of calcium back into the SR takes longer than its release
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excitation-contraction (EC) coupling is...
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sequence of events by which transmission of AP along the sarcolemma leads to sliding of myofilaments
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E-C coupling happens when?
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during latent period
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the binding of what causes the myosin head to detach from the actin?
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ATP
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Rigor Mortis is..
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stiffening of muscles after death, shows cross bridge detachment is ATP driven
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if muscle tension develops but load is not moved...
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isometric
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if muscle tension developed overcomes load and muscle shortening occurs...
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isotonic
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a motor unit consists of
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a motor neuron and all the muscle cells it innervates
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muscle twitch is...
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the response of a motor unit to a single AP of its motor neuron
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phases of twitch myogram...
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latent period
period of contraction period of relaxation |
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graded muscle responses are
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variations in the degree of muscle contraction by changing either the frequency or strength of the stimulus
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prolonged tetanus leads to
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muscle fatigue
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muscle fatigue is
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muscle is unable to contract and tension drops to 0
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the recruitment process is dictated by
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the size of muscle fibers
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treppe is
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the pattern shown for muscles warming up
stairs |
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muscle tone is
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low levels of contractile activity in relaxed muscle
keeps muscle healthy and ready to react |
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concentric contraction
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isotonic in which the muscle shortens and does work
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eccentric contraction
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muscle generates force as it lengthens (50% more forceful than concentric contractions)
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Name the 3 ways ATP is generated
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creatine phosphate
anaerobic pathway (glycolysis) aerobic respiration |
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direct phosphorylation
(energy source, product, duration, oxygen used?) |
energy source: creatine phosphate (cp)
product: 1 ATP, Creatine Duration: 15 seconds no oxygen used |
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anaerobic (glycolysis)
(energy source, product, duration, oxygen used?) |
energy source: glucose
product: 2ATP, lactic acid duration: 30-60 seconds no oxygen used |
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aerobic
(energy source, products, duration, oxygen used?) |
energy source: glucose, pyrovic acid, free fatty tissue from adipose tissue, amino acids from protein catabolism
products: 38 ATP, CO2, H2O duration: hours oxygen used |
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what % ATP used for muscle activity comes from aerobic?
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95%
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muscle fatigue
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state of physiological inability to contract
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contracture
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lack of ATP
ex: writers cramp |
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oxygen debt
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extra amount of oxygen required after exercise to replenish stores of O2,ATP, creatine phosphate, and glycogen, and oxidize the lactic acid formed during exercise
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how much energy released during muscle contraction is converted to useful work?
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40%
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force of muscle contraction is affected by these 4 things...
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# of muscle fibers stimulated
relative size of the fibers frequency of stimulation the degree of muscle stretch |
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hypertrophy
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increase in muscle size
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disuse atrophy
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degeneration and loss of mass
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the connective component of smooth muscle is
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endomysium
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source of calcium in smooth muslce
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SR and extracellular fluid
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site of calcium regulation for smooth muscle
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calmodulin in sarcoplasm
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peristalsis
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wavelike contractions that move foodstuff through the alimentary tube organs
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dense bodies
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act like z discs of skeletal muscle, anchor points for thin filaments of smooth muscle
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contraction method is alike for smooth and skeletal muscles by
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actin and myosin interact by the sliding filament mechanism
the final trigger for contraction is a rise in the intracellular calcium ion level sliding process is energized by ATP |
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smooth muscles ends contractile activity when
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Calcium levels drop and dephosphorylation of myosin heads by a phosphorlyase enzyme
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the smooth muscle's moderate degree of contraction =
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smooth muscle tone
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neurotransmitters in skeletal muscle and smooth muscle are
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Ach in skeletal
Lots of different ones in smooth |
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stress-relaxation response
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allows hollow organ to fill or expand slowly to accommodate a greater volume without promoting strong contractions that would expel contents
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hyperplasia
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smooth muscle fibers divide to increase their #'s
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smooth muscle is categorized into 2 types
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single unit and multi-unit
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muscle tissues develop from embryonic mesoderm cells called..
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myoblasts
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duchenne muscular dystrophy
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seen in more males, don't live beyone early 20's, clumsy, die of respiratory failure (lack dystrophin)
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muscle loss by aging
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sarcopenia
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intermittent claudication
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limping, restricts blood in legs=painful
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the plasma membrane of a muscle cell is known as
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sarcolemma
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4 functional groups of muslces
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prime movers
antagonists synergists fixators |
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circular fascicular pattern means
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squeezers, sphincters, arranged in concentric rings
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convergent muscle
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has broad origin, fascicles converge toward a single tendon of insertion (ex: pectoralis major)
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pennate
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fascicles are short and attach obliquely
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when the effort is farther from the fulcrum than is the load..
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the lever operates at a mechanical advantage (slow and strong)
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when the effort is exerted closer to the fulcrum than is the load..
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the lever operates at a mechanical disadvantage
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First class levers operate at a..
Second class levers operate at a... Third class levers operate at a... |
1.(effort-fulcrum-load)mechanical advantage or disadvantage.
2.(fulcrum-load-effort)mechanical advantage 3. (fulcrum-effort-load) always operate at a mechanical disadvantage |
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Explain what a 'DHP Receptor' is and where it is located
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Dihydropyridine, located in SR and opens Calcium channels in SR
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Curare Poisoning
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When Ach Receptors are blocked
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Botulism
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Prevents release of Ach
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Exposure to Malathion
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Contractions don't end, spastic paralysis
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Myasthenia Gravis
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Receptors are sparse (auto-immune disease)
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What happens if Ach is blocked?
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Muscle can't contract (flaccid paralysis)
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What happens if Ach receptors are sparse?
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Reduced muscle strength (flaccid paralysis and myasthenia gravis)
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What happens if Ach receptors are blocked?
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Flaccid paralysis, curare, bungarotoxin
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What happens if Ach-ase is missing or ineffective?
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Contraction doesn't end
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Anaerobic Threshold
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the point where aerobic changes to anerobic
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Describe relationship between internal tension, external tension, and the series elastic component
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external tension=internal tension - series elastic component
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Describe how asynchronous activation of motor units produce steady muscle tone
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so muscle fibers don't fatigue, they are stimulated at different times to keep contraction going.
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