Human Body temperature

Body temperature

Temperature is the 'hotness' or 'coldness' of a substance.

Body temperature is the difference between the amount of heat produced by body processes and the amount of heat lost to the external environment.

Heat produced - Heat lost  =  Body temperature.

Normal body temperature: For healthy young adults the average body temperature is 37º C (98.6` F). The body tissues and cells function best in the normal body temperature.

Core temperature is temperature of deep tissues. Despite extreme in environmental condition and physical activity, the temperature - control mechanisms of the human beings maintains the body' s core temperature constant.

Surface temperature fluctuates depending on blood flow to the skin and the amount of heat lost to the external environment.

Temperature - control mechanism of human beings

The body temperature is precisely regulated by physiological and behavioral mechanisms. For body temperature to stay constant and with normal range, the relationship between heat production and heat loss must be maintained.

The relationship is regulated by neurological and cardiovascular mechanisms. The nurse applies knowledge of temperature control mechanisms to promote temperature regulation.

Neural and vascular control

The hypothalamus located between the cerebral hemispheres, controls the body temperature.

The hypothalamus senses main changes in body temperature.

The anterior hypothalamus controls the heat production.

A comfortable temperature is the ' set point' at which a heating system operates.

When the nerve cells in the anterior hypothalamus became heated beyond the set point, impulses are sent out to reduce body temperature.

Mechanisms of heat loss include sweating, vasodilatation (widing) of blood vessels and inhibition of heat production.

If the posterior hypothalamus senses the body temperature is lower than the set point, heat conservation mechanisms are instituted.

Vasoconstrction (narrowing of blood vessels) reduces blood flow to the skin and extremities.

Heat production is stimulated through voluntary muscle contraction and muscle shivering.

Trauma to the hypothalamus or to the spinal cord (which carries hypothalamic tract) can cause serious alternations in temperature control.

Heat production:

Thermoregulation requires the normal function of heat - production processes. Heat is produced in the body by metabolism which is the chemical reaction in all body cells. Activities requiring additional chemical reactions increase the metabolic rate.

As metabolism increases additional heat is produced. When metabolism decreases, less heat is produced. Heat production occurs during rest, voluntary movements and involuntary shivering (shivering is an involuntary body response to temperature differences in the body). Shivering can increase heat production 4 to 5 times greater than normal.

Heat is produced to equalize body temperature.