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the degree of sensible heat or cold, expressed in terms of a specific scale. See Table of Temperature Equivalents in the Appendices. Body temperature is measured by a clinical thermometer and represents a balance between the heat produced by the body and the heat it loses. Though heat production and heat loss vary with circumstances, the body regulates them, keeping a remarkably constant temperature. An abnormal rise in body temperature is called fever.

Normal Body Temperature. Body temperature is usually measured by a thermometer placed in the mouth, the rectum, or the auditory canal (for tympanic membrane temperature). The normal oral temperature is 37° Celsius (98.6° Fahrenheit); rectally, it is 37.3° Celsius (99.2° Fahrenheit). The tympanic membrane temperature is a direct reflection of the body's core temperature. These values are based on a statistical average. Normal temperature varies somewhat from person to person and at different times in each person. It is usually slightly higher in the evening than in the morning and is also somewhat higher during and immediately after eating, exercise, or emotional excitement. Temperature in infants and young children tends to vary somewhat more than in adults.
Temperature Regulation. To maintain a constant temperature, the body must be able to respond to changes in the temperature of its surroundings. When the outside temperature drops, nerve endings near the skin surface sense the change and communicate it to the hypothalamus. Certain cells of the hypothalamus then signal for an increase in the body's heat production. This heat is conducted to the blood and distributed throughout the body. At the same time, the body acts to conserve its heat. The arterioles constrict so that less blood will flow near the body's surface. The skin becomes pale and cold. Sometimes it takes on a bluish color, the result of a color change in the blood, which occurs when the blood, flowing slowly, gives off more of its oxygen than usual. Another signal from the brain stimulates muscular activity, which releases heat. Shivering is a form of this activity—a muscular reflex that produces heat.

When the outside temperature goes up, the body's cooling system is ordered into action. Sweat is released from sweat glands beneath the skin, and as it evaporates, the skin is cooled. Heat is also eliminated by the evaporation of moisture in the lungs. This process is accelerated by panting.

An important regulator of body heat is the peripheral capillary system. The vessels of this system form a network just under the skin. When these vessels dilate, they allow more warm blood from the interior of the body to flow through them, where it is cooled by the surrounding air.
Abnormal Body Temperature. Abnormal temperatures occur when the body's temperature-regulating system is upset by disease or other physical disturbances. fever usually accompanies infection and other disease processes. In most cases when the oral temperature is 37.8°C (100°F) or over, fever is present. Temperatures of 40°C (104°F) or over are common in serious illnesses, although occasionally very high fever accompanies an illness that causes little concern. Temperatures as high as 41.7°C (107°F) or higher sometimes accompany diseases in critical stages. Subnormal temperatures, below 35.6°C (96°F) occur in cases of collapse; see also symptomatic hypothermia.
absolute temperature (T) that reckoned from absolute zero (−273.15°C), expressed on an absolute scale.
basal body temperature (BBT) the temperature of the body under conditions of absolute rest; it has a slight sustained rise during the luteal phase of the menstrual cycle and can be used as an indirect indicator of when ovulation has occurred.
body temperature the temperature of the body of a human or animal; see temperature.
core temperature the temperature of structures deep within the body, as opposed to peripheral temperature such as that of the skin.
critical temperature that below which a gas may be converted to a liquid by increased pressure.
normal temperature the body temperature usually registered by a healthy person, averaging 37°C (98.6°F).
risk for imbalanced body temperature a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as a state in which an individual is at risk of failure to maintain body temperature within the normal range.
subnormal temperature temperature below the normal. See also symptomatic hypothermia.


Abbreviation for basal body temperature.


basal body temperature.


abbreviation for basal body temperature.


n See technique, Buteyko breathing.
References in periodicals archive ?
Our knowledge evolved in areas of thermoregulation, normal variations in BBT, and the role of thyroid pathology on BBT.
2) He argues that BBT is a more accurate and more convenient predictor of thyroid status than both BMR and blood cholesterol.
Then you are down in a riparian forest, primarily oak and some sycamore - big trees,'' said Webster, who designed and directed the building of much of the BBT described herein.
Day hiking thus remains the preferred method of experiencing the BBT, and, with car shuttles, the entire Backbone Trail can be covered in four or five days by those who are both ambitious and fit.
th] interest per share) on BB&T's Series F Non-Cumulative Perpetual Preferred Stock (NYSE: BBT PrF)
th] interest per share) on BB&T's Series G Non-Cumulative Perpetual Preferred Stock (NYSE: BBT PrG)
When the state threatened to abandon the project in the mid 1970s, Brown led a petition drive that netted tens of thousands of signatures and put the BBT back on track.
While Sherman has been working the phones in Washington, Brown last month worked his way into a VIP reception for Vice President Al Gore to slip him a packet of BBT literature.
The results are available in the Other Disclosures section of the Investor Relations site on BBT.
In the process of developing the new devices, BBT designed an entirely new and elegantly simple fully downloadable conditional access solution that provides a high level of signal security, which can now provide a low-cost substitute for expensive CableCARD technology currently in use.
A live audio webcast of the event will be available through BBT.