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123 Cards in this Set
- Front
- Back
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What characteristics are shared by cardiac muscle and single-unit smooth muscle?
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functional syncytium
autonomicity |
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What characteristics are shared by skeletal muscle and multi-unit smooth muscle?
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motor unit composition
motor nerve required |
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What is equivilent to Z-lines in smooth muscle?
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dense bodies
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What kind of muscle cells are multinucleated?
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skeletal muscle
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What kind of muscle cells are mononucleated?
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smooth muscle
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What kind of coupling do desmosomes provide for cardiac monocytes?
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mechanical coupling
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What kind of coupling do gap junctions provide for cardiac monocytes?
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electrical coupling
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What kind of connection provides mechanical coupling for cardiac monocytes?
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desmosomes
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What kind of connection provides electrical coupling for cardiac monocytes?
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gap junctions
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What lies between cardiac monocytes?
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intercalated disc
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What are the major components of the connective tissue that surrounds nerves and blood vessels?
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collagen and elastin
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What wraps around a muscle fiber?
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endomysium
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What wraps around a muscle fascicle?
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perimysium
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What wraps around an entire muscle?
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epimysium
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What does endomysium wrap around?
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muscle fiber
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What does perimysium wrap around?
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muscle fascicle
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What does epimysium wrap around?
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entire muscle
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What is the flow of muscle growth during development?
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myoblasts --hyperplasia--> many myoblasts
--cell fusion--> myotubes --hypertrophy-->myofibers (w/satellite cells) |
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What is the diameter of a myofibril?
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1 um
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What is the subcellular source of muscle striations?
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myofibrils
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What line lies in the middle of a sarcomere?
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M line
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What line lies at the end of a sarcomere?
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Z line
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What is the area between thin filaments in a sarcomere called?
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H zone
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What is the area between thick filaments in a sarcomere called?
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I band
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What is the area that spans the length of the thick filament called?
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A band
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What makes up a myosin molecule?
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two myosin heavy chain subunits
four myosin light chains |
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What blocks the myosin binding site on actin during the relaxed state?
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tropomyosin
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What protein helps set the length of the thin filament in a sarcomere?
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nebulin
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What protein keeps thick filaments centered in the sarcomere?
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titin
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What is the function of nebulin?
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helps set the length of the thin filament in a sarcomere
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What is the function of titin?
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keeps thick filaments centered in the sarcomere
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What protein mediates a link between the myofibrillar proteins and the extracellular matric?
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dystrophin
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What is the function of dystrophin?
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links myofibriliar proteins to the extracellular matrix and ameliorates sheer stress during myofiber shortening
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What type of motor unit is recruited first?
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type I
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What type of motor unit is recruited last?
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type II
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Which type of motor unit has a larger diameter nerve?
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type II
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Which type of motor unit has a faster conduction velocity?
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type II
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Which type of motor unit has a higher excitability?
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type I
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Which type of motor unit has more myofibers?
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type II
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Which type of motor unit has a larger diameter myofiber?
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type II
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Which type of motor unit produces more force?
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type II
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Which type of motor unit uses oxidative metabolism?
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type I
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Which type of motor unit uses glycolytic metabolism?
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type II
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Which type of motor unit has a faster shortening velocity?
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type II
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Which type of motor unit has greater resistance to fatigue?
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type I
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What subunits make up an acetylcholine receptor?
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2 alpha, 1 beta, 1 delta, 1 gamma
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How many acetylcholine molecules make up a quantum?
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10,000
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What induces the open conformation of an acetylcholine receptor?
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binding of 2 acetylcholine molecules
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What flows through an acetylcholine receptor?
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sodium in
potassium out |
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What is a mini end plate potential?
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potential change induced by release of one acetylcholine vesicle (0.4 mV)
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What causes a decrease in end plate potential?
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curare and myasthenia gravis
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What causes an increase in end plate potential?
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neostigmine
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How does curare affect end plate potential?
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blocks receptors and decreases end plate potential
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How does myasthenia gravis affect end plate potential?
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reduces the amount of receptors and decreases end plate potential
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How does neostigmine affect end plate potential?
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provides additional receptor sites and increases end plate potential
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Where are ryanodine receptors loacted?
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sarcoplasmic reticulum
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Where are dihydroxypyridine receptors located?
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t-tubules
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What induces calcium release in cardiac muscle?
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calcium
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What induces calcium release in skeletal muscle?
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voltage change
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What type of calcium release does cardiac muscle have?
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graded
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What type of calcium release does skeletal muscle have?
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all-or-none
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Where does calcium come from in cardiac muscle?
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sarcoplasmic reticulum and extracellular fluid
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Where does calcium come from in skeletal muscle?
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sarcoplasmic reticulum
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What does the SR-Ca pump move?
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2 sodium out and 3 calcium in
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What are five characteristics of contraction?
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crossbridge cycle is repetitive
crossbridge cycle is asynchronous tension is proportional to crossbrige number velocity is proportional to cycle rate velocity is inversely proportional to load |
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What causes crossbridge attachment?
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addition of calcium
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What causes crossbridge motion (power stroke)?
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release of ADP
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What cause crossbridge detachment?
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ATP binding
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What energizes the crossbridge?
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ATP hydolysis
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What is the flow of the crossbridge cycle?
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A + MºADPºPi -->
AºMºADPºPi --> AºM --> A + MºATP |
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What part of a muscle is responsible for active tension?
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contractile component
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What part of a muscle is responsible for passive tension?
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parallel elastic component
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What part of a muscle must be stretched in order to develop active tension?
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series elastic component
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What is the contractile component of a muscle responsible for?
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active tension
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What is the parallel elastic component of a muscle responsible for?
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passive tension
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What is the series elastic component of a muscle responsible for?
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active tension (must be stretched)
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How long is the latent period for a muscle twitch?
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10 msec
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Which ATPase is responsible for the contraction time of a fiber twitch?
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myosin-ATPase
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Which ATPase is responsible for the relaxation time of a fiber twitch?
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SR-Ca-ATPase
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How can the force of muscle contraction be increased?
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increase the frequency of nerve stimulation
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What are the criteria for the active state?
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calcium binding to troponin C
crossbridge formation ATP hydrolysis crossbridge motion |
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Which muscle type operates over a broader range of cell lengths?
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cardiac
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What is leverage factor defined as?
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load arm/power arm
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Which ATPase maintains ion gradients and osmotic balance?
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Na-K-ATPase
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Which ATPase provides energy for crossbridge motion?
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Myofibrillar ATPase
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What ATP pathway is the least effective?
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creatine phosphate
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Which ATP pathway is the most effective?
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oxidative phosphorylation (36 ATP)
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How many ATP are produced by anaerobic glycolysis?
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2-3
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What is the first complex of the electron transport chain?
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NADH dehydrogenase
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What is the second complex of the electron transport chain?
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succinate dehydrogenase
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What is the third complex in the electron transport chain?
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cytochrome b-c1
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What is the fourth complex in the electron transport chain?
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cytochrome c oxidase
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What is the fifth complex in the electron transport chain?
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ATP synthase
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What is anaerobic threshold?
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point at which blood lactate accumulation becomes exponential
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What is the name for the point at which blood lactate accumulation becomes exponential?
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anaerobic threshold
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What is the difference between a trained athlete and untrained individual?
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athlete's aerobic consumption plateaus later
athlete's anaerobic threshold is greater |
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What is the staining difference between type IIA and type IIB muscle fibers?
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type IIA fibers stain intensely for oxidative enzymes
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What is the staining difference between type I and type II muscle fibers?
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type II fibers stain intensely for contractile protein
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What muscle fiber type has the most glycolytic activity?
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type IIB
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Which muscle fiber type has the most oxidative activity?
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type IIA
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Which muscle fiber type has the most mitochondria?
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type IIA
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Which muscle fibers are considered slow twitch?
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type I
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Which muscle type has the lowest fatigue resistance?
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type IIB
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Which type of muscle fibers are used for sustained tonic activity?
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type I
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Which type of muscle fibers are used for sustained phasic activity?
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type IIA
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Which type of muscle fibers are used for short term phasic activity?
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type IIB
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What change in fiber type proportion is achieved with long-term endurance exercise?
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increase in type IIA
decrease in type IIB |
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What is the major adaptive response to endurance exercise?
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increased oxidative capacity
limited myofiber hypotrophy |
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What is the major adaptive response to strength exercise?
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hypertrophy of myofibers
enhanced glycolytic capacity |
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What kind of fatigue is caused by myathenia gravis?
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neuromuscular fatigue
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What kind of fatigue is caused by issues around energy metabolism?
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cellular fatigue
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What are the elements of a monosynaptic reflex arc?
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receptor - muscle spindles acting as mechanoreceptors
afferent innervation - flower spray and annulospiral afferent nerves efferent innervation - alpha motor neurons effector - extrafusal fibers |
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What kind of nerves innervate nuclear bag fibers?
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primary afferent nerves
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What kind of nerves innervate nuclear chain fibers?
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primary and secondary afferent nerves
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What do spindles respond to?
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degree of stretch (static)
rate of stretch (dynamic) |
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What is the purpose of gamma efferent motor neurons?
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maintain spindle sensitivity during a contraction
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What is the function of a golgi tendon organ?
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monitor the force generated by a muscle
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What monitors the force generated by a muscle?
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golgi tendon organ
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Which part of the brain is responsible for externally generated movement?
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premotor cortex
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Which part of the brain is responsible for self generated movement?
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supplementary motor cortex
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What kind of movements is the premotor cortex responsible for?
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externally generated movements
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What kind of movement is the supplementary motor cortex responsible for?
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self generated movements
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What structures have the largest areas of the motor homunculus produced by somatotopic mapping?
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hands, fingers, and facial muscles
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