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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 |