Thermoregulation Flashcards
normal range of body temperature is considered to be
36.2° to 37.7° C
96.2° to 99.4° F
What mechanisms are in place to regulate temperature?
The hypothalamus, and endocrine system. Peripheral thermoreceptors
Where are these located?
Skin, liver, skeletal muscles. Central thermoreceptors in hypothalamus, spial cord, viscera, and great veins
Where are these located that regulate temperature?
Skin, liver, skeletal muscles. Central thermoreceptors in hypothalamus, spial cord, viscera, and great veins
Heat produced as by
chemical reaction metabolism, skeletal muscle contraction and thermogenesis by raising basal metabolic rate
Heat loss
Radiation, conduction, convection, vasodilation, evaporation, decrease muscle tone, increase respiration, voluntary mechanisms, adaptation to warmer climate
Hypothermia temp
below <35 C
below <95 degree F
What can happen with severe Hypothermia?.
if severe, ice crystals can develop inside the cells causing cellular rupture and death.
When would you use a therapeutic hypothermia
short term in OR or after cardiac arrest to preserve tissue from ischemia (an inadequate blood supply to an organ or part of the body, especially the heart muscles.)
When would a fever be beneficial
temporary hypothalamic reset of temp
Hyperthermia Temp
40 or 41° C
104 -105.8° F
nerve damage can produce convulsions in the adult due to
Hyperthermia
Death results at what temp
43° C
109.4° F
Fever temp
> 38.3 C
99.5-100.9 F
Mechanisms of Heat Production
Description:
Occur during ingestion and metabolism of food and while maintaining body at rest (basal metabolism); occur in body core (e.g., liver)
Condition:
Chemical reactions of metabolism
Mechanisms of Heat Production
Description:
Gradual increase in muscle tone or rapid muscle oscillations (shivering)
Condition:
Skeletal muscle contraction
Mechanisms of Heat Production
Description:
Epinephrine is released and produces rapid, transient increase in heat production by raising basal metabolic rate; quick, brief effect that counters heat lost through conduction and convection; involves brown adipose tissue, which decreases markedly in older adults; thyroid hormone increases metabolism
Condition:
Non-shivering thermogenesis
Mechanisms of Heat Loss
Description:
Heat loss through electromagnetic waves emanating from surfaces with temperature higher than surrounding air
Condition:
Radiation
Mechanisms of Heat Loss
Description:
Heat loss by direct molecule-to-molecule transfer from one surface to another, so that warmer surface loses heat to cooler surface
Condition:
Conduction
Mechanisms of Heat Loss
Description:
Transfer of heat through currents of gases or liquids; exchanges warmer air at body’s surface with cooler air in surrounding space
Condition
Convection
Mechanisms of Heat Loss
Description:
Diverts core-warmed blood to surface of body, with heat transferred by conduction to skin surface and from there to surrounding environment; occurs in response to autonomic stimulation under control of hypothalamus
Condition
Vasodilation
Mechanisms of Heat Loss
Description:
Body water evaporates from surface of skin and linings of mucous membranes; major source of heat reduction connected with increased sweating in warmer surroundings
Condition
Evaporation
Mechanisms of Heat Loss
Description:
Exhausted feeling caused by moderately reduced muscle tone and curtailed (reduced) voluntary muscle activity
Condition
Decreased muscle tone
Mechanisms of Heat Loss
Description:
Air is exchanged with environment through normal process; minimal effect
Condition
Increased respiration
Mechanisms of Heat Loss
Description:
increasing body surface area available for heat loss; dressing in light-colored, loose-fitting garments
Condition:
Voluntary mechanisms
Mechanisms of Heat Loss
Description:
Gradual process beginning with lassitude, weakness, and faintness; proceeding through increased sweating, lowered sodium content, decreased heart rate, and increased stroke volume and extracellular fluid volume; and terminating in improved warm weather functioning and decreased symptoms of heat intolerance (work output, endurance, and coordination increase; subjective feelings of discomfort decrease)
Condition:
Adaptation to warmer climates
