Topic 8 Thermoregulation Flashcards
Homeostasis
regulation of an internal environment in the face of changes in the external environment
Sensor
detects environmental conditions
neg feedback is
homeostatic
integrators
analyzes signals from sensor, compares conditions to the set point and activates an appropriate effector
Effector
causes an physiological change that opposes the deviation from the set point
sensory receptors to integrator (type of neuron)
afferent
Integrator to effectors (type of neuron)
efferent
Positive feedback Mechanisms +ex (3)
A change in a variable under homeostatic control triggers a response that amplifies the change
no shutting off until stimulus is removed
Ex: baby rush cervix, stimulus secretes oxytocin, oxytocin carried to uterus via blood stimulates uterus o contract more
Ta (3)
Ambient temperature
dictates how much energy animals need to spend to thermoregulate
room temp
Constant body temp importance (2)
enzymes can function normally
allows animals to expand and live in diff habitats
byproduct of metabolism
Heat
heat can be exchanged with the environment by
conduction, convection, and radiation
conductance
rate of heat exchange
explain what ectotherm and endotherm do with body heat
ectotherm just release, no thermoregulate
endotherm generate body heat to thermoregulate
large organism and conductance relationship
large organisms have lower conductance due to smaller SA/V ratio
Smaller organisms and conductance relationship
larger sa/v ration so higher conductance
Homeotherms (2)
Maintains “Constant body temp” independent of ambient temp
can be endotherm or ectotherms
Heterotherm+advantage+ ex (3)
body temperature fluctuates with ambient tempt
*advantages of reducing metabolic rate
Ex: fresh water fish whose Tb changes with seasonal changes in the water temp
Endotherms (2)
Uses metabolism to generate body heat
internal heat generation
Ectotherms (2)
Acquires body heat from temperature in environment
external heat source
Regional heterothermy +ex (2)
different between different regions of the body. Organisms that are able to maintain different temperature zones in different regions of the body
ex: if you take a fish, a measure the temp, the closer it s to the skin, the more its like water temp
countercurrent heat exchange system
a mechanism where warm blood from inner bodies is pumped out to their extremities next to the cold blood running back inwards The 2 blood temp participate in heat exchange and cold blood is warmed before re-entry to the body core
Fundamental concept (2)
Endotherms have higher RMR the ectotherms
Ectotherms with same body mass have much lower RMR
Regardless of endo and ecto whats the relationship btwn mass and msmr?
as body mass increase, mass specific metabolic rate goes down as the SA:V ratio decreases as animal increase in size
Total metabolic rate and rmr relationship and difference
Total metabolic rate is porportional to RMR the difference btwn the two is rmr doesn’t account for your active metabolic rate
as temp increase, there is a proportional change between rmr and total metabolic rate
at low temp, enzymes are
inactive
At high temp, enzymes are
denatured
rmr vs ambient temp graph. homeothermic
slide 16 topic 8
how to reduce heat loss
decrease exposure/ sa
what body will do to thermoregulate at hypothermia (5) *Term solutions
homeotherms
shivering
vasoconstriction (minimize heat loss)
philoerection (fur stands up and traps air inside insulting the insulating layer of air around body)
decrease SA ( fold into ball)
decrease exposure (burrowing)
What body will do in hyperthermia *Term solutions
homeotherms (5)
panting (When air comes in contact with the most pinning of lungs, it helps animal reduce its body temp
vasodilation
sweating
increase SA
decrease exposure (to sun)
low conductance is an adaptation (such as…) for (2)
heat retention
(fats/fur)
high conductance is an adaptation (such as) for (2)
heat loss
thin skin
for arctic animals, temp…
does not impact metabolic rate du to adaptations
Ambient temp and metabolic rate in a heterethermic ectotherm
pg19 topic 8
lethargy (2)
slow and inactive movements while the animals are awake – they are moving, but slowly.
conserving energy
grouping (2)
huddling tgt to share radiation
ex: reposting help bat reduce metabolic expenditure on temp regulation
Tarpor (4)
Use of non-shivering thermogenesis during recovery
Approximate 10°C drop in body temperature
A few hours duration
Reduced metabolic rate
getting ready for migration
store energy reserve
exercise certain muscles
acclimation
organisms adjust their cellular conditions to work optimally in cold and warm environments
vasoconstrictions in endotherms
when cold to retain heat
Vasoconstriction in ectotherms
when hot to retain heat
Vasodilation for ectotherms
when cold to retain heat
how does animals are up from hibernation
non shivering thermogenesis
