2. Thermoregulation Flashcards
What are the bodies heating mechanisms?
basal metab rate - determines rate of metab of nuts. and rate of skeletal muscle contraction: generates heat
What are ways the body absorbs heat from the surrounding? or is generated/aquired
Absorbed:
Conduction - direct heat
Convection - heat transfer from body to surrounding
Radiation - absorption of infra-red energy
Aquired:
Piloerection
Vasoconstriction
Behavior responses (nesting)
Shivering
What are the body’s cooling mechanisms?
Decrease metab rate
deep tissue heat transferred to skin
Evaporation (sweating/panting)
vasodilation
behavioral responses
What are the normal temperatures for dogs, cats, cattle and equines?
K9, Fel - 38.5 +/- 0.5 degree (above 39.1 must be reported)
Cattle - 38.5 +/- 0.5
EQ - 38.0 +/- 0.5
Normal ranges for hyperthermia and hypothermia (death)
43 °C and above – rapidly fatal
28 °C – dying
Another name for fever
pyrexia, physiological hyperthermia
What is a fever?
A purposeful increase in body temp. (>39.1) as part of inflam response
appropriate in event of infection
Heat causes denaturation of bact + viral proteins
How do you treat a fever?
treat underlying problem
NSAIDS
passive cooling - fans, cool towels, fluids
What is pathological hyperthermia?
when there is 1 an excessive heat generation or/and 2 cannot cool off fast enough
What are intrinsic risk factors for hyperthermia?
obesity, long haircoal/wool coats/ dark fur, dehydration, underlying cv or resp disease, genetic predispotion to specific drug reactions, strenuous exercise
what are extrinsic risk factors for hyperthermia
enviro temp approaches body temp (loss of convection)
>80 humidity (decreases evaporation)
over-crowding/poor ventilation/shipping and transport/capture stress
water deprivation
What is heatstress?
Mild hyperthermia = heat exhaustion
39.1 - 41.5
Often sublinical. if present -
Lethargy, sweating, panting, decreased prod
inc temp inc metab demand by muscle
how do you treat heat stress?
passive surface cooling - shade, proper ventilation, dec ambient temp, fants, misting, decrease density, water
What is heat strok
Severe hyperthermia
Core body temp exceeds 41.5, any temp above 43 is critical
What is the pathology of heat stroke
Intcell proteins denature + mitochondria stop fun - cell damage - cell death
dehydration, resp alkalosis
blood away from core to cool, lack of tissue perfussion