Since humans are warm blooded, why is the body not able to maintainnormal temperature when we have fever?
Meerut, Uttar Pradesh
Normally, the healthy normal temperature is maintained by an area in the brain called thermostatic centre, or temperature regulatory centre. This is just in front of an area called hypothalamus in the brain.
Experimentally, if any physical, chemical toxins approach this area, there is gross derangement in the temperature regulation of the body . One such example is malaria toxin, which affects this area, and increases the temperature. Similarly, toxins, trauma, and stroke (discontinuation of blood supply) etc, do cause the same type of injury to this centre, causing dys-regulation of temperature.
The thermostatic centre does get affected in increase in environmental temperature and this is the cause of heat strokes. The thermostatic centre comprises a group of neurons, which look after the body temperature, which are connected to the other regulatory centres.
For example, when your temperature increases, it dilates the skin blood vessels through autonomic nervous system, so that the sweat glands get lot of blood supply,. enabling them to prepare the sweat. Once the sweat forms over the skin, it evaporates, taking the body temperature, making the body more cooler.
It shuts down the renal blood supply, so that kidney receives less of blood supply, urine secretion is diminished, to enable the body to divert the blood the skin area to prepare the sweat. At the same time, in cooler climates,it causes vaso constriction of cutaneous blood vessels, sweat is lessened, to keep the body quite hot , protecting the body to keep enough temperature , and it compensates by passing more urine out put, which will not cause loss of body heat.
Multiple mechanisms, are involved in regulating the body temperature, but everything is ordered from brain, in the thermostatic centre, which oscillates to function depending on the body and environmental temperature. If the mechanism , function of these thermostatic neurons fail, the body temperature rises.
Dr. V. NAGARAAJAN
Professor Emeritus in Neuro Sciences
Tamil Nadu Dr MGR Medical University
Madurai, Tamil Nadu
