Final answer:
A fever acts as an immune response in the body by raising the body temperature to help fight off infections. Chemicals called endogenous pyrogens are released when the body is infected and they circulate to the hypothalamus, increasing the body's temperature to kill pathogens. A fever is a normal defense mechanism.
Step-by-step explanation:
A fever acts as an immune response in the body by raising the body temperature to help fight off infections. When the body is infected by bacteria, chemicals called endogenous pyrogens are released into the blood. These pyrogens circulate to the hypothalamus and reset the thermostat, increasing the body's temperature. This increase in temperature helps to kill pathogens, conserves iron which reduces a nutrient needed by bacteria, and increases the activity of the body's enzymes and protective cells to fight off the invading microorganisms. A fever is considered a normal defense mechanism rather than a complication of an infection.