Final answer:
Pyrogenic relates to the induction of fever, making 'A. Fever' the correct match with the term. Pyrogens trigger an increase in body temperature as part of the immune response to defend against pathogens.
Step-by-step explanation:
The medical term pyrogenic refers to something that causes or induces a fever. Therefore, the correct answer to match the term 'pyrogenic' with its closest definition is A. Fever.
Pyrogens are substances, typically produced by a bacterium, which affect the hypothalamus in the brain and raise the set point for body temperature, resulting in fever.
Fever is considered a systemic effect of inflammation rather than a cardinal sign, which includes redness, swelling, heat, and pain at the site of injury or infection.
Cardinal signs are local responses to inflammation, whereas fever can be seen as a body-wide response.
Explanation of Fever as an Immune Response
Fever is the body’s natural response to infection and is induced by pyrogens released by leukocytes when they destroy bacteria or in response to certain other immune system signals.
The fever helps inhibit the growth of pathogens since many bacteria and viruses thrive at normal body temperature, but become less efficient at higher temperatures.
Moreover, a fever increases immune system efficiency by promoting leukocyte mobility and T cell activation.