Skeletal Muscle Flashcards
How do we actually move our muscles?
Contracting and relaxing our muscles. (Shortening and lengthening our muscles)
When you see a term with sarco- in it what do you think?
It’s in/apart of muscle!
Define Sarcoplasmic reticulum
The calcium storage for muscle cells.
Define T tubules
Series of tunnels that start at Sarcolemma and deep into muscle fibers.
Enables action potential to reach all parts of the muscle fiber.
Explain on a molecular level how we are able to contract our muscles.
Troponin has to be bound to calcium to move out of the way to make myosin connect to actin filament to make “walking” movement.
Define:
I band
H zone
M line
Putter edge of A band.
In a relaxed state, what is happening in the muscle fiber?
What imitates contraction of muscle fiber?
In the 5 step initiation of contraction in the muscle cell, what’s happening in this step?
In the 5 step initiation of contraction in the muscle cell, what’s happening in this step?
In the 5 step initiation of contraction in the muscle cell, what’s happening in this step?
In the 5 step initiation of contraction in the muscle cell, what’s happening in this step?
In the 5 step initiation of contraction in the muscle cell, what’s happening in this step?
How does it go from this, to detached?
What’s the next step after this?
What’s the next step after this?
What’s the next step after this?
Define Excitation-Contraction Coupling reaction, where does it happen?
Action potential comes from somatic motor neuron
Releases Ca++ into sarcolemma(muscle membrane).
This binds neuron to membrane and releases ACh, which triggers action potential in T-Tubule.
This potential travels in T-Tub. And comes in contact with DHP.
Depolarization causes conformational change of DHP which triggers RyR to open letting Ca++ into muscle fiber.
Bind to troponin, enabling contraction.
What comes after this step in the initiation of contraction?
What comes after this step in the initiation of contraction?
Start of excitation-contraction coupling!
What comes after this step in the Excitation-Contraction Coupling?
What comes after this step in the Excitation-Contraction Coupling?
What comes after this step in the Excitation-Contraction Coupling?
What comes after this step in the Excitation-Contraction Coupling?
What comes after this step in the Excitation-Contraction Coupling?
Start of relaxation phase!
What comes after this step in the Relaxation Phase?
What comes after this step in the Relaxation phase?
What is determining the length and slope of the bottom graph?
Amount of calcium in sarcosol.
Define slow versus fast, twitch fibers.
Fast Twitch has extreme fatigue. Slow by comparison doesn’t.
What do you look for in order to determine if it is a slow or fast twitch muscle fiber? Why?
Color! Dark=Slow, Light=Fast
Summary Slide!
