What term refers to processes or reactions that affect the whole body?

The term that refers to processes or reactions affecting the whole body is "systemic." This concept is crucial in understanding how certain conditions, medications, or reactions can impact not just a specific part but the entire organism.

For instance, systemic infections can spread through the bloodstream, influencing multiple organs and systems, leading to more severe health outcomes than localized infections, which are confined to one area. Similarly, systemic medications are designed to achieve an effect that permeates throughout the body rather than targeting a single site. This broad effect is essential in treatments that need to address widespread issues, such as metabolic disorders or systemic inflammation.

While localized refers to effects that are restricted to a specific area, segmental may imply processes that affect segments or specific parts but not the entire body. Centralized generally suggests a focus on a core or central part but does not encompass whole-body processes. Thus, the term "systemic" accurately captures the concept of widespread impact within the body.