Term
| A single AP produces a weak contraction called |
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Definition
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Term
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Definition
time between initiation of stimulation and start of contraction
action potential is traveling at this time
[image]
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Term
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Definition
time between onset of contraction and peak tension
continues until all calcium removed
[image]
[image]
[image]
[image] |
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Term
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Definition
Time between peak tension and complete relaxation
[image]
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Term
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Definition
Single AP: Single Twitch (Calcium immediately removed and contraction stops)
Two AP close together: Summation of Twitch
(released Ca binds to troponin then is removed but additional AP releases more Ca so contraction continues)
Multiple AP close together: Summation of Twitches
[image] |
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Term
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Definition
many rapid stimuli prevents muscle relaxation
increased AP: so much CA released maximum number of cross bridges exposed = maximal tension
all fibers recruited, no asynchronous recruitment, fatigue occurs
[image] |
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Term
| How does length of muscle fiber affect contraction? |
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Definition
optimal resting length maximal contraction
increasing length moves thing filaments away from thick filaments |
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Term
| ATP in Skeletal Muscle Fibers is Required for... |
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Definition
Energizing of Myosin Head requires splitting of ATP
Detachment of myosin cross bridge from actin requires binding of Fresh ATP
Active Transport of CA into Sarcoplasmic Reticulum requires energy (ATP) |
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Term
| ATP Sources for skeletal muscle |
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Definition
Creatine Phosphate (1st source)
Glycolysis + Krebs Cycle + Oxidative Phosphorylation
Anaerobic Pathways |
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Term
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Definition
energy reserves in resting muscle stored in CREATINE PHOSPHATE (5x more than ATP)
Creatine Phosphate + ADP <---> Creatine+ATP
(needs creatine phosphatase)
used during burst activity (less than 1min)
[image] |
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Term
| Glycolysis + Krebs Cycle + Oxidative Phosphorylation |
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Definition
Mitochondria in muscle require fuel (glucose) to produce ATP = 38 ATP/glucose
Slow compared to creatine phosphate
during aerobic endurance exercise
maximized oxygen delivery to muscles
[image]
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Term
| Glycolysis Alone (Anaerobic Pathway) |
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Definition
Makes ATP rapidly but only 2ATP/glucose
Rapidly depletes fuel supply (glycogen stores)
Produces Lactic Acid --> bad (soreness, fatigue, metabolic acidosis)
only possible for short time
[image]
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Term
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Definition
| when muscle can no longer respond to stimulation with same degree of contractile activity, probably because of lactic acid build up and depletion of energy sources |
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Term
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Definition
motor neurons cannot make Ach fast enough
(Physiological Fatigue, YOUR BODY CANT DO IT) |
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Term
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Definition
Psychological Fatigue
(You psyche yourself out and think you can't do it any more) |
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Term
| Is oxygen consumption elevated during recovery from exercise? |
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Definition
| Yes, because of oxygen DEBT |
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Term
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Definition
contractile energy debt from nonoxidative ATP sources (glycolysis alone, creatine phosphate) repaid during recovery
1. creatine phosphate made again
2. lactic acid metabolized
3. glycogen stores replenished |
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Term
| Recovery from General Metabolic Disturbance |
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Definition
all chemical reactions are still speeded up
still high levels of epinephrine
needs to be downregulated, still in sympathetic NS fight or flight |
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Term
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Definition
Slow oxidative (TYPE 1)
Fast Oxidative (TYPE 2)
Fast Glycolytic (TYPE 2a)
Slow oxidative recruited first b/c located in smaller motor units (small, slow force, high resistance to fatigue)
Fast oxidative next because found in intermediate motor units (medium force)
Fast glycolytic last, larger motor units (high intensity, large amt of force) ANAEROBIC activities |
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Term
| do skeletal muscles usually contain all three fiber types? |
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Definition
| yes, just in different proportions |
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Term
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Definition
| increased muscle fiber DIAMETER (gets bigger) |
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Term
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Definition
increased muscle fiber NUMBER (get MORE muscle fibers) by splitting
RARELY HAPPENS |
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