Homeostasis is the body’s process for maintaining balanced ranges of body systems such as temperature, hydration and energy intake. 

Homeostasis is essential for healthy bodies. The immune response contributes to homeostasis by helping to fight off infection and heal after infection or trauma. 

During an infection, molecules called pyrogens are released, which alert the brain to increase the temperature of the body, causing a fever. The fever inhibits the movement of bacteria and viruses, buying more time for the immune cells to find and eliminate the invaders.