thermoregulation Flashcards
endotherm hot
kangaroo panting: the saliva evaporates off the tongue cooling it down evaporation water - gas cooling licking wrists: as the saliva evaporates it cools the blood vessels underneath the wrists which is then circulated through the body and cools it evaporation water - gas cooling
endotherm cold
polar bear hair under paws: low conduction allows them to stay warmer for longer hair: is clear and hollow trapping warm air and reduces convection allows them to stay warmer for longer
penguin:
- counter current heat exchange
- think skin on palms and feet
- insulating blubber
- feathers for insulation
- huddling
- lean back and balance on their heels
ectotherm hot
marine iguana avoidance: burrows, shade, nocturnal
ectotherm cold
turtle basking: lie exposed to the heat and sun radiation energy transferred through empty space
kangaroo feedback loop
stimulus: rise in body temp receptor: thermoreceptors in skin and hypothalamus modulator: hypothalamus starts cooling method effector: glands in mouth, saliva glands, lungs response: panting feedback: lowers body temp
endotherm
heats body temp from an internal heat production straight line on graph
- mammals and birds
ectotherm
heats body temp from an external heat source fluctuates on graph
- reptiles, fish , amphibians
dogs pant when they get hot
- to regulate body temp - evaporate water form the mouth - circulate cool air through the body
you shiver on cold days
- brief contractions of muscles that produces heat
goose bumps on a cold day
muscles contract causing the hairs to stand up and surrounding to protrude trying to warm up the body
skin looks pink on hot days
when hot the blood vessels dilate becoming larger to attempt to cool the body filing with more blood
cats look fatter on a cold day
they fluff their fur and store fat to keep them warm, decreasing convection
people eat more during winter
cold weather causes metabolic activity to increase, people increase more to keep up with it in attempt to heat up their body
small mammal lose more heat then large
small body has a larger surface area to volume ratio causing them to lose more body heat
thermal window purpose
open during the day, close at night, reduces conduction
adaptive value of tucking legs under their body at night
reducing surface area to keep warm and sheltering the thermal windows so they can retain heat, ambient temp is unable to transfer into the body
explain how penguins reduce heat loss when standing on ice
- rock back onto heels - use a counter current exchange system
- warm artery moves from blood to feet
- cool vein moves from feet to heart
- heat is trasnfered from warm blood in the artery to cool blood in the vein
- blood is cooled by the time it reaches the feet reduing heat loss
after the injection from penguins
temp of the foot increases while body temp decreases. the muscle relaxant causes vasodilation decreasing the ability of the counter current exchange therefore causing the feet to heat up therefore losing more heat via conduction decreasing the overall temp of the body
rising the temp of the hypothalamus
made the animals think they were hot therefore causing them to try cool themselves down decreasing their body temp
lowering the temp of the hypothalamus
made the animals think they were cold therefore causing them to try heat themselves up increasing their body temp
negative feedback
when a response cancels or counteracts the original stimulus
is an echidna ability to go into torpor in cold conditions adaptive
yes because it doesn’t have to use a lot of energy to survive, in cold conditions food is scarce by not regularly eating and by lowering metabolic rate they are able to survive for longer then if were awake
how can an echidna generate body heat to wake up from torpor
generate body heat by having an increase in their metabolic rate as they wake up functions such as shivering allows muscles to conduct warmth throughout their body they can also fluff their fur to trap heat and keep warm
what would you expect about its oxygen consumption if its generates its own heat
oxygen consumption increases as their metabolic rate increases, the heat beats faster and they breathe faster
do platypus like cold or warm water
warm because it requires less energy to generate body heat
can platypus regulate body temp in cold water
yes because they are an endotherm
suggest how a platypus might produce heat to regulate its body temp
muscles activity, through activities such as swimming the muscles contract causing them to warm up
suggest how a platypus might reduce heat loss to regulate body temp
burrows, reducing convection and conduction by burrowing in warm, humid spot out of water and wind
radiation
energy transferred through empty space occurs wihtout direct contact
conduction
occurs when the temp of the organism and the environemtn are different
- result of direct contact
convection
- transmission of heat from a warmer region to a cooler region from the movement of liquid or gas
- air con
evaporation
water - gas cooling
- occurs as energy is lost through a phase state change from water to water vapour
- occurs rapidly when the air is hot and dry
endotherm and ectotherm
red is endotherm, les energy to stay warm when temp increases then uses energy to cool down
blue is ectotherm as rate increases when temp incresses as they need to cool the body down
homeostasis
the maintanence of a constant internal environmental despite changes in the external environment
- maintains optimal conditions for enzyme activity and cell functions
feedback loop functions of stages
- stimulus : a change in the internal or external environemtn
- receptor: sensory structure in the body which detects the stimulus and sends signal to modulator
- modulator: centre in the brain which regulates the necessary action
- effector: structure in the body that receives signals from the modulator and carries out the action needed eg muscle or gland
- response : action carried out by the effector
positive feedback
- response amplies the direction of the stimulus
feedback loop for thermoregulation hot
- increase in body temp above normal
- increase detected by thermoreceptors in the skin and in the hypothalamus
- hypothalamus sends signals via nerve and hormones to effectors
- sweat glands, blood vessels in skin, body cells
- increase in sweating, vasodilation of blood vessels in the skin, decrease metabolic rate, behavioural changes
feedback loop for thermoregulation cold
- decrease in body temp below normal
- decrease detected by thermoreceptors in skin and hypothalamus
- hypothalamus sends signals via nerve and hormones to effectors
- blood vessels in skin, skeletal muscles, body cells
- vascontriction of blood vessels in skin, shivering, increased metabolic rate, behavioural change
endotherm vs ectotherm
ectotherm : metabolic rate increases with increase in temp
- can survive on less food
- low water requirment
endotherm: metabolic rate remains constant with increaseing temp
- needs high inputs of food to survive
- high water requirment
