Lecture 14 - Skeletal Muscle Flashcards
What are the inherent properties of myosin?
Binds actin
ATPase
What are the thick and thin filaments?
Thick: myosin
Thin: actin
What are the inherent properties of actin?
Binds to myosin
Activates mATPase
ATP binding to myosin brings about …
Detachment of the myosin head from actin
Hydrolysis of ATP brings about …?
Cocking of the myosin head
When does the myosin head bind to actin?
After the head cocks
What brings about the power stroke?
Detachment of the phosphate from the myosin head
Wen does ADP detach?
After the powerstroke
What is the rigor state?
After the power stroke when the myosin head is still bound to the actin
Within a single muscle, how can the maximum contraction velocity change?
The muscle must lift a heavier load –> lesser Vmax
What is the power of the muscle equal to?
P = Cross sectional area x length
What is being propagated along the surface membrane of the skeletal muscle?
APs
Behaving very much like the axon, because it has:
• voltage sensitive channels
How does the AP get from the surface membrane into the centre of the skeletal muscle fibre?
T tubules
How does an AP going down a T tubule result in release of Ca from the SR?
T tubules couple with RyR that open up on the SR, letting Ca flow down the concentration gradient into the cytosol
What is the difference between fast and slow twitch muscle?
Fast: greater density of SR
Slow: lesser density of SR
