Final answer:
A fever is triggered by endogenous pyrogens released by white blood cells, causing the hypothalamus to raise the body's temperature set point. It helps fight infections by hindering pathogen reproduction, boosting white blood cell production, and sometimes killing pathogens, but very high fevers can be dangerous.
Step-by-step explanation:
Fevers are caused by the presence of pyrogens in the blood, which can be a result of immune system responses to a pathogen or another perceived threat. Specifically, when white blood cells destroy bacteria, they release endogenous pyrogens. These chemicals travel to the hypothalamus in the brain and reset the body's thermostat to a higher temperature, thus causing a fever.
The role of a fever in fighting infection is to create an environment that is less favorable for the invading pathogens. A higher body temperature slows down the reproduction of most bacteria and viruses, increases the production of white blood cells, accelerates tissue repair, and can directly kill some pathogens. However, very high fevers can be dangerous, potentially leading to tissue and organ damage or life-threatening conditions such as toxic shock syndrome and scarlet fever, when caused by bacterial superantigens.