Not the why of them but the how of them.
In: 8
Your body has something called a “set point” for temperature. If your body temperature is below that set point, it activates processes like shivering and burning fat molecules found in brown fat to warm you up. If your body temperature is above that set point, it activates processes like sweating and dilating the blood vessels near your skin. The actual regulation here is done by the hypothalamus, a small part of the brain that handles automatic functions within the body (it also regulates, for example, hunger and sleepiness).
A fever is triggered by the production of a signaling molecule called PGE2, which signals the hypothalamus to raise the set point. Since your normal body temperature is below this new set point, this triggers the same processes that would normally occur if you were very cold. (This is why you shiver and “feel” cold when you have a fever: your body is responding as though you *are* too cold.)
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