(centigrade temperature) temperature expressed on a scale in which the melting point of ice is assigned a temperature of 0° and the boiling point of water a temperature of 100°. For many medical purposes this scale has superseded the Fahrenheit scale (see Fahrenheit temperature). The formula for converting from Celsius (C) to Fahrenheit (F) is: F = 9/5C + 32. [A. Celsius (1701–44), Swedish astronomer]
Body temperature is the result of a balance of heat-generating forces, chie?y METABOLISM and muscular activity, and heat-loss, mainly from blood circulation through and evaporation from the skin and lungs. The physiological process of homeostasis – a neurological and hormonal feedback mechanism – maintains the healthy person’s body at the correct temperature. Disturbance of temperature, as in disease, may be caused by impairment of any of these bodily functions, or by malfunction of the controlling centre in the brain.
In humans the ‘normal’ temperature is around 37 °C (98·4 °F). It may rise as high as 43 °C or fall to 32 °C in various conditions, but the risk to life is only serious above 41 °C or below 35 °C.
Fall in temperature may accompany major loss of blood, starvation, and the state of collapse (see SHOCK) which may occur in severe FEVER and other acute conditions. Certain chronic diseases, notably hypothyroidism (see THYROID GLAND, DISEASES OF), are generally accompanied by a subnormal temperature. Increased temperature is a characteristic of many acute diseases, particularly infections; indeed, many diseases have a characteristic pattern that enables a provisional diagnosis to be made or acts as a warning of possible complications. In most cases the temperature gradually abates as the patient recovers, but in others, such as PNEUMONIA and TYPHUS FEVER, the untreated disease ends rapidly by a CRISIS in which the temperature falls, perspiration breaks out, the pulse rate falls, and breathing becomes quieter. This crisis is often preceded by an increase in symptoms, including an epicritical rise in temperature.
Body temperature is usually measured on the Celsius scale, on a thermometer reading from 35 °C to 43·3 °C. Measurement may be taken in the mouth (under the tongue), in the armpit, the external ear canal or (occasionally in infants) in the rectum. (See also THERMOMETER.)
Treatment Abnormally low temperatures may be treated by application of external heat, or reduction of heat loss from the body surface. High temperature may be treated in various ways, apart from the primary treatment of the underlying condition. Treatment of hyperthermia or hypothermia should ensure a gradual return to normal temperature (see ANTIPYRETICS.... temperature
the temperature of the body, as measured by a thermometer. Body temperature is accurately controlled by a small area at the base of the brain (the *hypothalamus); in normal individuals it is maintained at about 37°C (98.4°F). Heat production by the body arises as the result of vital activities (e.g. respiration, heartbeat, circulation, secretion) and from the muscular effort of exercise and shivering. A rise in body temperature occurs in fever.... body temperature
temperature expressed on a scale in which the melting point of ice is assigned a temperature of 32° and the boiling point of water a temperature of 212°. For most medical purposes the Celsius (centigrade) scale has replaced the Fahrenheit scale. The formula for converting from Fahrenheit (F) to Celsius (C) is: C = 5/9(F – 32). See also Celsius temperature. [G. D. Fahrenheit (1686–1736), German physicist]... fahrenheit temperature
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