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46 Cards in this Set
- Front
- Back
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Smooth muscle |
Spindle-shaped (fibers) 1 nucleus Involuntary |
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Cardiac muscle |
Cylindrical fibers Striated 1 nucleus involuntary |
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Skeletal |
Cylindrical fibers multinucleated Striated Voluntary |
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All three muscle tissues share? |
Excitability contractility elasticity |
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4 Functions of the skeletal muscle? |
1. movement 2. support 3. heat production 4. tendons of muscles stabilize joints |
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Structure & contraction of skeletal muscle? (Large to small) |
muscle to fascicle to myofiber to myofibril to myofilaments |
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fascia= |
dense CT covering entire muscle. Continuous with tendons connecting to bone. |
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epimysium= |
CT closest to muscle; circles entire muscle. |
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perimysium= |
Covers each fascicle (bundle of fibers) |
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Endomysium= |
Covers each individual myofiber. |
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Plasma membrane=sarcolemma |
T (transverse) system; tubules dip into cell. |
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Cytoplasm= |
Sarcoplasm |
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ER=Sarcoplasm Reticulum: |
Stores Ca +2; surrounds myofibrils |
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Sarcoplasm has lots of? |
mitochondria. ATP for contraction. |
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Myofibrils= |
Cylindrical cords composed of protein filaments. Lie parallel as extend through length of fiber. |
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myosin- |
thick filament |
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actin- |
thin filament |
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myofilaments? |
contractile proteins that slide past one another, which creates a contraction. |
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Sarcomere (contractile unit): |
working unit of skeletal muscle fiber. organized pattern of contractile proteins. (Z-Z) |
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Sliding filament theory= |
muscle contraction. when actin and myosin slide past one another. |
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3 Things a muscle contraction requires? |
1. innervation=nerve stimulus 2. Ca +2 3. ATP |
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Lots of heat produced during excersize because? |
Crossbridges for between actin & myosin. Some Ca +2 pumped back to SR, some released as heat. |
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motor unit? |
1 motor neuron stimulating many muscle fibers (25-3000) |
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neuromuscular junction? |
where motor neuron meets each muscle fiber. |
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innervation? |
skeletal muscle contraction. |
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6 Steps of innervation? |
1. impulse travels down motor nueron to NM junction. 2. neuron releases ACh 3. ACh travels across synaptic cleft to plate of fiber, to sarcolemma T system to SR. 4. SR releases Ca +2 5. Ca +2 to myofibrils 6. Crossbridges form/ATP activated. filaments slide causing sarcomere to shorten =contraction. |
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3 ways energy is acquired for contraction? |
1. Cellular respiration 2. Creatine phospate breakdown. 3. Anaerobic glycolysis |
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What does "all or none" response mean? |
each muscle fiber contracts completely or not at all. (increase in strength is due to # of fibers contracting) |
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3 Types of contractions? |
1. Twitch 2. Summation 3. Tetany= max. sustained contraction (fatigue if not allowed to rest. EX: running) |
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Tone= |
small # of fibers stay contracted, important to maintain posture. Involves special receptors=muscle spindles |
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Hypertrophy= |
increase in muscle size. Increased myofibrils within fiber, may also involve increase in fibers. |
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atrophy= |
decrease in muscle size due to nerve damage, broken bones etc. |
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Flexion= |
decreases angle ex: bending arm |
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extension= |
increase in angle ex: straighten arm |
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abduction= |
lateral away from midline. ex: lifting leg to side |
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adduction= |
back toward midline |
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rotation= |
ex: turning arm so palm faces forward/backward |
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circumduction= |
ex: circle arms |
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inversion/eversion= |
toes in/toes out |
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elevation/depression |
ex:shrugging shoulders |
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origin= |
place where muscles attach to more stationary bone. |
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insertion= |
place where muscles attach to more movable bone. |
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group action= |
prime movers & synergists work together. |
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antagonists= |
opposing muscles ex: biceps & triceps |
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isotonic movement= |
muscle contracts/shortens = movement of body part. |
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isometric movement= |
muscle contracts/ doesn't shorten. =No movement. ex: when you push against a wall. |
