How do fevers occur?

Answer 1

Fever is a physiological response, or symptom, of something else happening in the body. Common causes of fever include an infection (a cold, flu, bacterial infection, etc.), a disease, cancer, and many other causes.

.

An portion of the brain, called the hypothalmus, regulates the body's temperature. It is similar to a thermostat in a building. Fever occurs when some condition in the body (above) casues the hypothalmus to raise the body's set temperature.

.

When the hypothalmus increases the body's set temperature, the body increases its temperature by constricting blood vessels (reduces heat loss through the skin) and by increasing the liver's metabolism, thus increasing the internal heat generated. An excited hypothalmus also leads to shivering - the involuntary shaking of large muscles, which also generates heat.

.

A mild fever (100 to 102F, or 37 to 38C) actually helps the body's immune system defend against infection, and therefore a mild fever is a productive response to fighting an infection. When a fever reaches 104F (40C), the fever itself begins to interfere with the body's ability to function efficiently, and a fever of over 106F (41C) is life threatening.

Answer 2

Stimulation of the cell wall by a bacteria/virus or trauma leads to the release of prostaglandins. These prostaglandins have an effect in the hypothalamus in the brain, which then resets your 'standard' temperature control for your body. Your hypothalamus increases your body's temperature in order to fight off the infection, virus, or to speed healing by increasing your metabolic rate.

Having a fever forces you to feel cold, so you try to warm yourself up beyond your normal temperature. Also, fever acts in waves, so feeling hot and cold with a flu is actually the brain sending your temperature up and down to fight off infection.

Answer 3

Fevers are the body's reaction to accelerated white blood cell prodution. Basically, if you get an infection, then your body tries really hard to fight it and the increased effort is manifested as an increase in body temperature.