Physio: Regulation of Temperature Flashcards
Range of normal core temperature of the body.
36-37.5 C
Main form of energy (heat) exchange between the body and the environment.
Radiation (60%)
Only two types of heat transfer that occur in the core.
- Conduction: thru tissues
- Convection: thru blood flow
(all 4 types occur at the skin’s surface)
Region of the hypothalamus known as the “Heat Loss Center” that responds to increased body temp by increasing sweating and stimulating vasodilation.
Anterior (pre-optic) area
Region of the hypothalamus known as the “Heat Production Center” that responds to low body temperatures by stimulating metabolism and vasocontriction.
Posterior Area
Both exercise and fever increase body temperature. What is the difference in the mechanisms of how this temperature is increased?
- Exercise results in increased metabolism mainly by skeletal muscle which generates heat mainly in the blood flow.
- Fever actually changes the “Set Point” that the hypothalamus uses to regulate body temperature and the hypothalamus will raise the body temperature to coincide with the NEW set point.
What is hyperthermia and what 3 things does the body do to regulate it?
Hyperthermia is a body temp above the set point.
- Vasodilation
- Sweating
- Reduced heat production
What chemical mediator prevents excessive electrolyte loss during intense sweating when the body is trying to lose heat?
Aldosterone
-encourages reabsorption of sodium and chloride ions in the sweat gland ducts
What is hypotermia and what 3 things does the body do to regulate it?
Hypothermia is a body temperature lower than the set point.
- Vasoconstriction/Venoconstriction
- Thermogenesis
- Piloerection (minor in humans)
Describe the mechanism of Cold Diuresis.
During hypothermia blood is sent to the core to keep internal organs warm.
The increased blood flow to the kidneys stimulates a false sense of hypervolemia resulting in increased urine production.
In response to hypothermia, what are the 4 mechanisms involved in increased thermogenesis?
- Shivering
- Brown fat lipolysis
- increased thryoid hormone release
- Epi and NE release
During exercise the venous return to the heart decreases due to increased blood flow to the skeletal muscles. How does the heart maintain blood flow to the periphery to dissipate heat even with the decreased cardiac output?
Increased heart rate.
During exercise, why does the body shunt blood away from the splanchnic and renal vasculature?
Volume loss in occuring thru sweating and this is a response to maintain the body’s water storage.
Pyrogenic mediator that influences the hypothalamic neurons to increase firing leading to incraesed body temp and a new set point.
PGE 2
What is the most common mechanism of heat exhaustion?
Failure of cardiovascular response to dissipate heat.
