Muscle Flashcards
Skeletal and cardiac muscle have very similar contractile mechanisms but what is the difference between the two muscle types?
Voltage-dependent calcium channels in the t tubules
In skeletal muscle the depolarisation causes a conformational change in a DHP receptor that is physically bound to ryanodine receptors. There is NO calcium influx. In cardiac muscle there is a voltage dependent calcium channel in the t tubule and there is not a physical interaction with the ryanodine receptor. Troponin is the calcium sensor in both and tropomyosin suppresses actomyosin formation in both types.
Activation of a voltage-gated sodium channel leads to a rapid and transient influx of sodium lasting about 2-3 ms.
Why is the current flow so brief?
The channel enters an inactive state quickly
