Term
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Definition
1.Skeletal= voluntary, striated, long (1000x), thick(20x), cylindrical, multi-nucleated, contract&relax rapidly(30x)
2.Smooth=involuntary, non-striated, short, thin, spindle shaped, 1 nucleus, contract&relax slowly
3.Cardiac=involuntary, striated, 1 or 2 nuclei, branched, intercalated discs |
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Term
| Levels of organization of a Muscle Fiber |
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Definition
1.Myosin(thick) and Actin(thin)= filaments/proteins
2.Sarcomere=functional unit of muscle/shortens
3.Myofibril=strand of sarcomere (80% cell volume)
4.Other Organelles=mitochondria, sarcoplasmic reticulum
5.Sarcolemma=cell membrane; deep in cell (t-tubules)
6.Muscle Fiber=muscle cell
7.Muscle=many fibers together; much CT
8.CT=run vessels through; around each:
-cell=endomysium
-fascicle=perimysium
-muscle=epimysium |
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Term
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Definition
| -myosin -crossbridges= actin binding site and myosin ATPase site |
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Term
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Definition
-actin, tropomyosin, troponin
-actin helix= myosin binding site; double strand of beads
-tropomyosin=threadlike proteins that cover myosin binding site
-troponin=hinge; binds Ca2+ and moves tropomyosin |
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Term
| Muscle Contraction: Sliding Filament Mechanism |
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Definition
1.Change in thin filament-->myosin binding site is open
2.Activate the crossbridge and power stroke
3.Thin Filaments pull together into the H zone
4.Z-lines move closer together
*think and thin filaments dont change in length, they just OVERLAP more |
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Term
| Excitation-Contraction Coupling |
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Definition
-link between muscle excitation and contraction
-T tubules carry ATP
-sarcoplasmic reticulum stores ATP
-Ca2+ required for actin and myosin to interact and causes power stroke
-ATP must bind to crossbridge for it to release thin filament |
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Term
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Definition
1.Power stroke of crossbridge
2.Break actin-myosin bond
3.Ca2+ pumps working to remove Ca2+ back into sarcoplasmic reticulum |
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Term
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Definition
-one motor neuron plus all the muscle fibers it innervates
-vary in size, depending on the use of the muscle
-fine control=small units
-power=large units |
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Term
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Definition
-increase recruitment to generate more power
-increase strength of contraction by:
1.larger # units activated
2.larger units
-spatial summation
-increase tension in individual muscle fiber= "TTT":
1.Temporal summation
2.Time-"piggy back" (^frequency)
3. Tetanus(no time to relax) |
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Term
| Energy sources for skeletal muscle activity |
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Definition
1.Use limited storage of ATP
2.Conversion of creatine phosphate (donates PO4 to ADP-->ATP)
3.Glycolysis (aerobic or anaerobic): fast pathway; high intensity but short
4.Oxidative Phosphorylation(aerobic): 0xygen+fuel= high endurance and # ATP |
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Term
| Muscle Adaptation in response to use |
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Definition
1.Regular aerobic exercise:
-high # and size mitochondria
-high production oxidative phosporylatio
-high myoglobin concentration
-low lactic acid production
-high fat as burning fuel
-high circulatory pathways
2.short duration, high intensity exercise
-hypertrophy=increased cell size
3.no use or denervation- myosin and actin breaking down
-atrophy=decreased muscle size
4.Muscular dystrophy- progressive degeneration of contractile elements; hereditary pathological condition |
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Term
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Definition
1.Red Slow Twitch (oxidative):
-high myoglibin and mitochondria
-aerobic
-high ATP
-thin,slow contraction,high endurance
-found in lower back
2.White Fast Twitch (glycolytic):
-low myoglobin and mitochondria
-anaerobic
-high storage of glycogen
-thick,fast contraction,fatigue rapidly
-found in arms
3.Red Fast Twitch (intermediate)
-high myoglobin and mitochondria
-aerobic
-in between,fast contraction
-found in legs
*All muscle fibers NOT created equal
*Athletes are born NOT made |
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Term
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Definition
-walls of hollow organs and tubes
-contain thick and thin filaments but NO troponin or tropomyosin
-NO sarcomeres or T tubules
-Ca2+ causes a chemical reaction:
1.enters from ECF
2.initiates reaction that result in
phosphorylation of myosin
3.myosin binds to actin & work/ratchetin |
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Term
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Definition
-neurogenic(neuron produced-->involuntary)
-functions like skeletal muscle but is innervated by autonomic neurons |
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Term
| Single-unit smooth muscle |
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Definition
-myogenic(nerve independent-->contractile)
-functional syncytium= tissue functions as one unit
-cells connected by gap junctions |
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