MUSCLE
What are the three types of muscle tissues?
Smooth muscle
Cardiac muscle
Skeletal muscle
What is recruitment
Activation of additional motor units to help in force production
What do satellite cells help with
Muscle growth, development, respond to injury, immobilization, and training
What is contractility
Ability to shorten when stimulated
What is an EMG similar to and why
ECG
Records the action potentials/depolarization of muscle fibers
The five properties of skeletal muscle are
Excitability
Conductivity
Contractility
Extensibility
Elasticity
What is the size principle
Which disk is actin anchored at
Z-disk
How does the power stroke end
Myosin detached from active sight and returns to its original position
Amplitude
What are the skeletal muscle functions
Force of production for locomotion
Heat production during cold stress
Very long multinucleated cells
What is the order of recruitment
Smallest to largest
Type I --> Type IIa--> Type IIx
Which is a thin filament and which is a thick filament
Actin is a thin filament
Myosin is a thick filament
When does the sliding filament theory end
AP stops, CA2+ gets pumped back into SR
What does the closer wave in succession represent
What does the functional motor unit of muscular contractions consist of?
An alpha motor nerve fiber and all of the muscle fibers (cells) it innervates
How are motor units normally recruited
Asynchronously
Which band contains both actin and myosin filaments
A-band
What is the difference between the relaxed state and contracted state
Relaxed: no actin-myosin interaction at binding side and myofilaments overlaps
Contracted: myosin head pulls actin towards center (power stroke) and filaments slide past each other
What is the amplitude envelope and where is it seen
Area under the curve
Integral EMG
Which fibers contain < 300 fibers/motor neuron and best for fine control
Slow twitch fibers
In recruitment, what can resistance training result in
More synchronous recruitment
What do myosin bind to and why
Actin filaments for contraction
What are the 6 steps to excitation-contraction coupling
1. Action potentials start in the brain
2. Action potentials arrive at axon terminal, releases ACh
3. ACh crosses synapse, binds to ACh receptors on plasmalemma
4. AP travels down plasmalemma, T-tubules
5. Triggers Ca2+ release form SR
6. CA2+ enables actin-myosin contraction
Which EMG signal is useful and why
Integral EMG
Shows only positive deflections