Final answer:
The statement that does NOT represent a role of ionic calcium in muscle contraction is that it triggers the diffusion of Na+ out of cells. Calcium's role is tied to activities such as myofilament sliding, neurotransmitter release, and the action potential related to sarcoplasmic reticulum calcium release.
Step-by-step explanation:
The statement that does NOT represent a role of ionic calcium in muscle contraction is: e. Triggers diffusion of Na+ out of the cells. The roles of ionic calcium in muscle contraction include triggering the sliding of myofilaments, stimulating ATPase activity, releasing calcium from the sarcoplasmic reticulum, promoting neurotransmitter release, and initiating a series of events that lead to muscle contraction through interaction with the troponin-tropomyosin complex, which exposes actin sites for cross-bridging with myosin heads.
However, calcium does not directly trigger the diffusion of Na+ out of cells; this process is associated with the action potential's depolarization and repolarization phases, involving sodium and potassium channels, not calcium.