Thermoregualtion

Thermal gradient

Temp difference between skin and surrounding environment

How does the body increase thermal gradient

Vasodilation

How does the body decrease thermal gradient

Vasoconstriction

Blubber/winter coat

Piloerection- increasing air temp

How will heat transfer change based on thermal gradient

Increase and decrease with each other

What is convection

Heat loss due to surrounding air/water

How can we decrease heat loss via convection

Decrease exposed skin, decrease air contact, Huddling

What will exchange heat loss via convection

Forced convection - breeze, fan, current

Constant renewal of cool air/water

What is conduction

Heat lost to in contact solid surface

What is radiation

Heat lost via invisible wave to distant objects

What is evaporation

Conversion of liquid to vapor

What needs to happen to increase heat loss via sweating

Vasodilation, sweat secretion

What is sweat similar to in composition

Plasma

What stimulates sweating

Sympathetic nervous system

what needs to happen to increase heat loss via panting

Vasodilation in lungs, rapid exchange of small volumes of air, increase salivation

What causes the Afferent temperature regulation response

When inputs don’t equal outputs

What is core temperature and what regulates it

Temperature of the brain; regulated by the hypothalamus

What causes efferent temperature responses

Outputs exceed inputs

When are heat conservation mechanisms initiated

Decrease in temperatures detected

When are what loss mechanism initiated

When high temps are detected

when are heat production mechanisms initiated

When low temps are detected

What is the initial response to heat stress

Vasodilation; increases thermal gradient

What is the initial cold stress response

Vasoconstriction and piloerection; decreases thermal gradient

Explain countercurrent heat exchange

Heat transferred from arterial blood to deep veins

What happens with chronic cold exposure

Increased basal metabolic rate and increased hair coat growth

What helps maintain the thermoneutral zone

Vasodilation and vasoconstriction

Do smaller animals have a higher or lower TNZ and why

Higher due to greater surface area for heat loss

What is pyrexia

Fever; increase in thermoregulatory set point

What are pyrogens

Peptides that stimulate hypothalamus to increase thermoregulatory set point

At what temperature does serious impairment of celluar function occur

107-109

What is hyperthermia

Abnormally high body temp

What affect does humidity have on evaporative heat loss and what species tend to be most effected

Decreases efficacy; problematic especially in dogs

What is hypothermia

Abnormally low body temperature; outputs greater than inputs

What is frostbite

Ice crystals in tissues causing cell damage and death; occurs at tissue temps below 32

What effect does anesthesia have on thermoregulation

Increases risk of hypothermia due to increased heat loss and vasodilation can only do so much.