Temperature Regulation
This article explores the concepts of body temperature regulation, focusing on core and skin temperature, and their responses to environmental changes. It defines core temperature as the deep tissue temperature, which remains stable unless a fever occurs. The mechanisms of heat production through metabolism, muscular activity, and hormonal influences are examined, alongside heat loss mechanisms such as radiation, conduction, and evaporation. Additionally, the impact of environmental factors like wind chill on skin temperature is discussed.
Temperature Regulation
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Presentation Transcript
Definitions • Core Temperature • Measured as oral, aural, or rectal temperature • Temperature of deep tissues of the body • Remains relatively constant (1ºF or 0.6ºC) unless a person develops a febrile condition • Nude person can maintain core temperature even when exposed to temperaturesas low as 55ºF or as high as 130ºF in dry air • Skin Temperature • Rises and falls with the temperature of the surroundings
Definitions • Core Temperature • Measured as oral, aural, or rectal temperature • Temperature of deep tissues of the body • Remains relatively constant (1ºF or 0.6ºC) unless a person develops a febrile condition • Nude person can maintain core temperature even when exposed to temperaturesas low as 55ºF or as high as 130ºF in dry air • Skin Temperature • Rises and falls with the temperature of the surroundings
Heat Production • Laws of Thermodynamics • Heat is a by-product of metabolism • Basal metabolic rate of all cells of the body • Effect of muscular activity on metabolic rate • Effect of endocrinology on metabolic rate (i.e., thyroxin, growth hormone, testosterone) • Effect of autonomic nervous system on metabolic rate
Heat Loss • How fast is heat transferred from deep tissues to the skin • How rapidly is heat transferred from the skin to the surrounding environment
How Fast Is Heat Transferred From Deep Tissues to Skin • Insulation Systems • Skin and subcutaneous tissue (i.e., fat) • Blood Flow • Cutaneous circulation
How Fast Is Heat Loss Fromthe Skin to the Surrounding Environment • Radiation • Conduction • Evaporation
Definitions • Radiation • Loss of heat by infrared heat rays (5-20m or 10-20X wavelength of visible light) • Conduction • Loss of heat from the body to a solid object • Evaporation • Loss of heat from the body through water vapor to the surrounding atmosphere • Convection • Effects of changes in the external environment (e.g., wind and water)
“Wind Chill Factor” • Effect of wind on skin temperature – temperature of calm air that would produce equivalent cooling of exposed skin • Cooling effect of air convection equals the square root of the wind velocity • For example, air temperature feels twice as cold at a wind velocity of 4 mph than if the wind velocity is 1 mph
