Which statement best defines inflammation?

• A. A nonspecific immune response to tissue injury or infection, characterized by warmth, redness, swelling, pain, and decreased function.
• B. An autoimmune attack against healthy tissues.
• C. A highly specific response that involves antibodies only.
• D. A process that always causes fever and chills.

Answer: (A)

Inflammation is the body's nonspecific response to tissue injury or infection. It acts broadly, not tailored to a particular pathogen, to contain damage, clear debris, and start healing. The warmth and redness come from increased blood flow, while swelling results from fluid leaking into tissues; pain arises from mediators like bradykinin and prostaglandins, and function may be impaired as a result of swelling and tissue injury. This contrasts with autoimmune attacks, which target the body's own tissues, and with highly specific antibody-driven responses that are part of the adaptive immune system. Fever and chills are not mandatory for inflammation—they can accompany systemic inflammation but aren’t required for the local inflammatory process. So the statement describing a nonspecific immune response to tissue injury or infection with these signs best defines inflammation.