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16 Cards in this Set
- Front
- Back
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Characteristics of synovial joints:
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1. articular cartilage
2. joint cavity (contains synovial fluid) 3. articular capsule 4. synovial fluid 5. reinforce ligaments 6. supply of nerve and blood vessels |
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Three functions of synovial fluid:
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1. lubricates the joint
2. shock absorption 3. nutrient and waste transport |
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Sacromere
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the basic contractile unit, runs from Z-disc to Z-disc
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Troponin- Tromyosin complex
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regulates contraction function of actin (thin filaments) and myosin (thick filaments)
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Calcium in skeletal muscle contraction:
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-is stored in the sacroplasmic reticulum (SR)
-nerve impulses cause its release -after it is released, myosin binding sites on actin filaments is liberated (enabling a contraction) -after contraction, calcium ions are transported back to the SR with the help of ATP |
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Uses of ATP:
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1. Before contraction, myosin has already hydrolyzed and ATP molecule (also at the end of the cycle)
2. This energy cocks the myosin head 3. In contraction step 4, ATP binds to the myosin head (the link between actin and myosin breaks) 4. Returning the calcium to the SR after contraction requires ATP 5. After contraction, ATP releases crossbridges |
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Phases of a muscle twitch:
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1. Latent: period before contraction, calcium released from SR (response to excitement)
2. Contraction: crossbridge activity causes contraction and tension develops 3. Relaxation: calcium is pumped back to the SR, muscle tension decreases, muscle returns to resting length |
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Tetanus:
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lacks partial relaxation between stimuli because of rapid succession of twitches, high Ca++ levels in the SR produce smooth and continuous reactions
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Isotonic:
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movement occurs and the muscle shortens, the tension is greater than the load (picking something up)
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Isometric:
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no movement, the load is more than the tension (holding you posture stationary)
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Ways to make ATP:
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-chemical reaction with ceratine phospate (CP)
-very fast reaction, support muscle contraction ~15 seconds -anaerobic mechanism -fast reaction, no oxygen required, occurs in cytoplasm, support muscle contraction 30-60 seconds -aerobic mechanism -slow reaction, oxygen is required, occurs in mitochondria, support prolonged muscle contraction |
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Hypertrophy:
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increase the size of muscle fibers, results in a more forceful contraction, testosterone increases the size, although you can never increase the amount
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Atrophy:
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wasting away of muscle, loss of mass due to inactivity
-disuse: reversible -denervation: replace fibers with fibrous connective tissue, irreversible |
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Characteristics of slow, red oxidative fibers:
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1. high blood flow
2. high myoglobin 3. high mitochondria 4. difficult muscle fatigue 5. smaller and less powerful |
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Characteristics of fast, white glycolytic fibers:
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1. low blood flow
2. low myoglobin 3. low mitochondria 4. easy muscle fatigue 5. larger and more powerful |
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Smooth muscle contractions:
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-results from neural stimulation by autonomous nervous system
-differs from skeletal: 1. no troponin or tropomyosin 2. regulation is not controlled by troponin-tropomyosin complex 3. myosin binding sites are always exposed 4. regulation is controlled by changes in ATPase activity of myosin |
