The document discusses the primary function of an action potential in a skeletal muscle fiber. It highlights that the action potential is involved in several processes, including the unwinding of tropomyosin off actin, the release of calcium from the sarcoplasmic reticulum, and the opening of voltage-gated sodium channels. The focus is on how these actions contribute to the cycling of myosin heads during muscle contraction.

1. Generally speaking, what is the direct function (purpose) of an action potential travelling down a
skeletal muscle fiber?
Group of answer choices:
To allow tropomyosin to unwind off of actin
To allow calcium out of the SR
To open voltage gated sodium channels
To allow for the myosin heads to cycle