biology-of-thermoregulation.pdf

lOMoARcPSD|28762649 Biology of Thermoregulation Biological and Learning Psychology (University of South Australia) Scan to open on Studocu Studocu is not sponsored or endorsed by any college o...

lOMoARcPSD|28762649 Biology of Thermoregulation Biological and Learning Psychology (University of South Australia) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Alexia Jones ([email protected])  lOMoARcPSD|28762649 BALP WK 6- BIOLOGY OF THERMOREGULATION Endotherms e.g. leatherback turtle, sea gull Biology of - Require a lot of food to fuel their high metabolism Thermoregulation - Minimise heat exchange with the external environment though insulating fur BEHAVIOURAL THERMOREGULATION using posture, orientation and/or microclimate Thermoregulation is a process that allows your - Can maintain a constant internal temp selection to regulate body temperature. body to maintain its core internal temperature. E.g. lizard wanting to increase temp will ‘spread ECTOTHERMS eagle’ (posture) on top of a hot rock (microclimate) DIFFERENT SYSTEMS FOR REGULATION OF BODY Cold blooded- poikilotherm: internal temperature and turn its back to the sun (orientation) TEMPERATURE: varies with ambient environmental temperature (not all ectotherms are poikilotherms) (fish, frog) TORPOR (MINI-HIBERNATION) Main source of heat is from the environment Reduced metabolic activity and body temperature Ectotherms for less than a day (endotherm) - require relatively little food e.g. bats, hummingbirds, small marsupials - depend on heat exchange with the external HIBERNATION environment Long-term torpor (can be 6 months) occurring in - internal temp changes with the the winter months (endotherms & ectotherms) to environmental temp changes conserve energy. E.g. squirrels, adders, bears ESTIVATION THERMOREGULATION Long-term torpor (can be 6 months) occurring in - insulation (fur, feathers, blubber, the summer months (ectotherms) to avoid damage colouration) from high temperatures (desiccation- extreme - metabolic heat production/physiological dryness/drying out) e.g. fish, frogs, snails thermoregulation TIMING OF ACTIVITIES - counter current heat exchange NOCTURNAL: active at night (owl, mice, koala) - behaviour DIURNAL: active during daytime (‘grazers’, PHYSIOLOGICAL THERMOREGULATION gazelles/elephants) Altering metabolic generation of heat to regulate CREPUSCULAR: active at dawn/dusk (deer, rabbits, temperature, e.g. metabolism increases to raise cats, red pandas, most birds) internal body temperature in a colder environment CATHERMAL: active at periods throughout 24 hours ENDOTHERMS METABOLIC ACTIVITY (some lemurs) Warm blooded- Homeotherms: maintain thermal Shivering, panting, evaporation of water from COOLING OFF TECHNIQUES homeostasis or keep body temp consistent respiration and/or sweating rolling or walling in mud, taking a ‘dip’ or standing in irrespective of ambient temp COUNTERCURRENT HEAT EXCHANGE water, going underground, using caves,, lying in Main source of heat is from own body through Warm and cold blood flow in opposite directions to shade, flying in high altitudes metabolic activity (dolphin, bear, leopard, human) regulate the temperature (arteries & veins) Usually around the brain/head region Downloaded by Alexia Jones ([email protected])  lOMoARcPSD|28762649 BALP WK 6- BIOLOGY OF THERMOREGULATION THERMOREGULATION: PATHOLOGIES HYPERTHERMIA: body temp too high, fever HYPOTHERMIA: body temp too low, metabolism THERMOREGULATION: HOMEOSTATIC BALANCING slows OF BODY TEMPERATURE Peripheral & body core receptors- sense change HYPOTHALAMIC THERMOREGULATORY CENTRE: integrates and initiates shivering, non-shivering thermogenesis and vasoconstriction. BODY TEMP BALANCE IN HOMEOTHERMS Metabolic heat production is usually required to maintain balance Balance is very narrow range, usually higher than environment THERMO NEUTRAL ZONE: represents ambient conditions where heat gain by animals equals heat loss (= thermal comfort; 28-31 CO in naked humans) SUMMARY EATING: provides carbohydrates, proteins, and fats for metabolism ENERGY: is used for body heat and work: transport, synthesis, storage METABOLIC RATE: changes with age, sex, body fat, THERMOREGULATION: PREVENTION OF activity and diet OVERHEATING INSULIN: regulates anabolic cell activities and SWEAT: evaporates from skin  cooling. glucose uptake in cells Vasodilation of cutaneous vessels transports heat MAINTAINING HOMEOTHERMY: takes approx. 50% from core. of our energy BEHAVIOUR: decrease in activity= decrease in HYPORHTALAMIC THERMOREGULATORY CENTER: exposure to heat controls heat homeostasis Downloaded by Alexia Jones ([email protected])  lOMoARcPSD|28762649 BALP WK 6- BIOLOGY OF THERMOREGULATION Downloaded by Alexia Jones ([email protected])