Reaction time and reflexes are influenced by inertia primarily in the physical response rather than the neural impulses. Increased mass or inertia can lead to a delay in physical actions, as heavier limbs or objects slow down muscular responses. The molecular dynamics of ion movement and membrane properties also play a role in signal transmission speed along neurons, but these factors remain constant. The discussion emphasizes that while neural initiation is unaffected, the physical execution of a reaction is hindered by increased inertia. Overall, understanding the relationship between inertia and reaction time is crucial for analyzing physical responses.