PATHOLOGY

Detailed explanation-1: -In the early stages of a fever, you often feel cold and start to shiver. This is your body’s response to a rising temperature. The blood vessels in your skin tighten up (constrict), forcing blood from the outer layer of your skin to inside your body where it is easier to keep the heat in.

Detailed explanation-2: -Temperature is ultimately regulated in the hypothalamus. A trigger of the fever, called a pyrogen, causes a release of prostaglandin E2 (PGE2). PGE2 then acts on the hypothalamus, which raises the temperature set point so that the body temperature increases through heat generation and vasoconstriction.

Detailed explanation-3: -muscle systems Shivering is muscle activity that generates heat and warms the body. Similarly, some insects vibrate their wings for a while before flight, heating the muscles to the temperature at which they work best. When an animal shivers in the cold, a large amount of heat is generated in the muscles.