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Muscular System
Question | Answer |
---|---|
Entire muscle is surrounded by —at the end forms a tendon | epimysium |
bundles of muscle fibers | fascicles |
surrounds fascicles | perimysium |
muscle cells-made of myofibrils | muscle fibers |
muscle cell membrane | sarcolemma |
stores calcium in muscle cell | sarcoplasmic reticulum |
muscle cell cytoplasm | sarcoplasm |
repeating units of filaments-contracting unit | sarcomere |
thick filaments | myosin |
thin filaments | actin |
Nerves and skeletal muscle fiber connect here | neuromuscular junction |
neurotransmitter that triggers muscle contraction | acetylcholine |
A muscle fiber contracts or doesn’t | all or none response |
single stimulus contraction relaxation sequence | twitch |
sustained contraction-stimuli arrive before relaxation complete | summation |
all muscle fibers controlled by a single neuron | motor unit |
increased tension produced by increase in the number of motor units | recruitment |
resting tension-partial sustained contraction | muscle tone |
contraction that moves the resistance | isotonic contraction |
contraction that doesn't move the resistance (pushing a wall) | isometric contraction |
Increased muscle size due to increased numbers of mitochondria, myofibrils, and glycogen reserves | hypertrophy |
decreased muscle size due to lack of stimulation | atrophy |
contract .01 seconds or less, large, powerful contractions, fatigue rapidly, “white color” | fast fibers |
½ size of fast, takes 3 times longer to contract, increased endurance, increased blood flow, red pigment (myoglobin) carries oxygen darker in color | slow fibers |
fast fibers, brief intensive workouts that stimulate hypertrophy | anaerobic endurance |
sustained low level workouts, jogging, distance swimming | aerobic endurance |