core temperature

temperature /tem·per·a·ture/ (tem´per-ah-chur)

1. an expression of heat or coldness in terms of a specific scale; a measure of the average kinetic energy due to thermal agitation of the particles in a system. Symbol .

2. the level of heat natural to a living being.

3. colloquial term for fever.

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absolute temperature  (T ) that reckoned from absolute zero (−273.15°C or −459.67°F), expressed on an absolute scale.

basal body temperature  (BBT) the temperature of the body under conditions of absolute rest.

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  that of the human body in health, about 98.6°F or 37°C when measured orally.

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core temperature

Etymology: L, cor, heart, temperatura

the temperature of deep structures of the body, such as the liver, as compared to that of peripheral tissues.

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Core Temperature

The body’s internal temperature, which is optimal at 37ºC; death generally occurs when the core temperature exceeds 42ºC; cardiac arrhythmias occur at 28ºC or below; asystole occurs at 20ºC

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temperature [tem´per-ah-chur]

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.

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temperature,

n the degree of sensible heat or cold.

temperature, body,

n the measurable temperature of the body. Normal range of variations, 98°F to 99°F (35.5°C to 37°C) orally and 99°F to 100°F (37°C to 38°C) rectally, with much wider ranges for skin.

temperature, body, regulation,

n homeostasis of body temperature. Results from a balance of heat production (external heat plus heat from muscle contraction and other chemical processes) and heat loss (through lungs, sweating, surface radiation, and excretions).

temperature, casting,

n the required degree of heat necessary to bring a metal to proper fluidity for introduction into a refractory mold.

temperature, core,

n the temperature of the internal tissues of the body, this temperature stays stable, unlike the temperature of the outer body surfaces, which are affected by the environment.

temperature, recrystallization,

n the lowest temperature at which the distorted grain structure of a cold-worked metal is replaced by a new, strain-free grain structure during prolonged annealing. Time, purity of metal, and prior deformation are important factors.