Certified Instrument Specialist (CIS) Practice Exam 2026 - Free CIS Practice Questions and Study Guide

Substances that induce fever upon introduction into the body are known as pyrogens. Pyrogens can be produced by the body itself in response to infection or inflammation, or they can originate from external sources, such as certain bacteria or viruses. When pyrogens enter the bloodstream, they signal the hypothalamus to raise the body's temperature, leading to a fever. This increase in body temperature is part of the immune response that helps the body fight off infections.

In contrast, antipyretics are medications designed to reduce fever, immunogens are substances that provoke an immune response, and analgesics are pain-relieving medications. Understanding the role of pyrogens in the body is crucial for recognizing how the immune system responds to pathogens and how fever can be both a symptom and a mechanism of defense.