Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
33 Cards in this Set
- Front
- Back
|
Development of Neuromuscular Junction - At birth |
-Multiple neurons influence a fiber |
|
|
Development of Neuromuscular Junction - Neuron "growing form spinal column |
- 1st 10 weeks of development, no nerve connections within muscles - Week 11-12, first connection of nerve with muscle fibers -ACH receptors are all over sarcolemma |
|
|
Poly-Neuronal Innervation |
-100s of axons "attached" to each fiber. -ACH receptors cluster under each axon |
|
|
Poly to Uni : Neuromuscular Junction -Neural Innervation |
-Excess K+ activates K+ACC (potassium activated calcium channels) - Ca2+ enters developing axons which activates Ca2+ activated proteases - Proteases breakdown axonal proteins -SURVIVAL OF THE FITTEST -Channels and proteases degraded om 30 minutes of neuronal innnervation |
|
|
Proposed Mechanism: Trophic Factor Hypothesis |
--> competition for muscle derived maintenance factor "synaptotrophin" |
|
|
Proposed Mechanism: Toxic Factor Hypothesis |
--> Elimination due to muscle-derived toxic substance "synaptotoxins" |
|
|
Proposed Mechanism: Retrograde Factor Hypothesis |
--> Intracellular factors- "synaptomedins" in the muscle triggered by active axon terminals selectively stabilizes and destabilizes active and inactive nerve terminals. |
|
|
3 Methods for Muscle Research --> In Situ (In Sight) |
-studying muscle w/ nerve and blood supply, isolated within body -Good for studies of metabolism - Can not get good velocity data |
|
|
3 Methods of Muscle Research --> In Vivo (In Life) |
- Study of muscle in whole organism -Excellent applicability since studying organism as it normally functions - Complex system makes it difficult to interpret due to undesired interactions |
|
|
3 Methods of Muscle Research --> In Vitro (In Glass) |
-Study of muscle when it is fully excised -Good for study of whole muscle or even a single fiber -Do not mimic human conditions |
|
|
Methods for Fiber Typing |
Contractile Properties: Slow/Fast Metabolic Properties: Oxidative/ Glycolytic Color Properties: Red/White Staining Properties: Enzymes/ pH |
|
|
Slow Twitch Fibers |
-Low myosin ATPase activity -slower Ca2+ release and uptake by SR -low glycolytic capacity -large and numerous mitochondria -small motor units -slow oxidative |
|
|
Fast Twitch Fibers |
-higher capacity to transmit AP -high myosin ATPase activity -rapid Ca2+ release and reuptake by SR -Capable of quick force generation -relies on anaerobic metabolism- high glycolytic |
|
|
Henneman Size Principal |
-Motor Unit Recruitment is small slow (I) to large fast (II) -even when applying large, rapid force, this holds true - Initially recuit type 1 --> small jumps in force, slow velocity, shallow rise - Recruit type 2a MU, bigger jumps in force, faster velocity, medium rise -Recruit type 2x, biggest jumps, fastest vel. |
|
|
E Stim Paper |
- E Stim reverses order of motor unit recruitment --> Type IIx , Type IIa, then Type I |
|
|
Muscle Types : Parallel |
-Fibers run parallel to the long axis of the muscle Strap Muscle- fibers originate and insert across entire width of broad flat tendon Lf = Lm ex. sartorius and rectus abdominis Fusiform- fibers originate and insert in one focuses area on the tendon Lf= Lm ex. bicep brachii |
|
|
Muscle Types: Pennate |
- All fibers not parallel but arranged on an angle |
|
|
Muscle Bulging |
-muscle is 75% H2O - Fibers are closed cylinders - can't compress H2O w/ physiological pressure -Same volume, different shape |
|
|
Pennate Muscles: 3 Types - Uni Pennate Muscle |
Ex. Soleus - Lf< Lm -Angle of pennation is between 5 and 20 degrees Aponeurosis- tendinous sheath along muscle --> give fibers something to attach to --> direct force to insertion and tendon |
|
|
Pennate Muscles: 3 Types - Bi-Pennate Muscle |
Ex. Rectus Femorus -Lf< Lm<> -Addition of central aponeurosis -Shorter fibers than Uni-pennate |
|
|
Pennate Muscles: 3 Types - Multi-Pennate Muscle |
Ex. Gastronemius, or temporalis -Lf < Lm<> -total of 3 central aponeurosis -Aponeurosis surround entire perimeter -shorter fibers than bi-pennate |
|
|
Force related to Pennation |
The smaller the angle of pennation, the larger the force directed at the tendon is . |
|
|
Aponeurosis |
-tendinous sheath along the muscle --> gives fibers something to attach to --> direct force to insertion and tendon |
|
|
Equation 1) |
Et- excursion of tendon Ef- exursion of fiber Et=Ef --- for parallel Et>Ef --- for pennated (every fiber shortens a certain distance, causes tendon to move a greater overall distance) |
|
|
Equation 2) |
Force on the Tendon = (Sum of each fiber)(cos0) |
|
|
Equation 3) |
CSA(m)(cm^2)= (muscle mass (mg)(cos0)/ (Lf(mm)Md(mg/mm^3)) Md- Muscle Density Muscle Deficet- percentage of force |
|
|
Hydrodynamics vs. Aerodynamics |
Bird: minimal bulging, aerodynamics Fish: minimal bulging, hydrodynamics |
|
|
Skeletal Muscle Architecture: Force and Length Relationship |
Graphs: |
|
|
Cat Semi-Tendinosous Muscle |
-Force is identical among all three -Difference in power output is due exclusively to velocity - Parallel strap muscle |
|
|
Human Performance Cape |
-Speed -Time -Resistance |
|
|
Peak Power |
Obtained at intermediate loads and intermediate velocities |
|
|
Three main categories of Adaptations |
-neural -contractile -elastic |
|
|
Protein Turnover |
-refkects 1/2 life of protein -protein transcribed (DNA--> RNA) |
