Thermoregulation Flashcards
What is homeostasis?
homeo (similar) stasis (state)
It it a dynamic process that is regulated by how the organism can change its behaviour/metabolism to maintain its internal environment to an acceptable range
what are the parameters that organisms must control?
pH,
water (volume and pressure of cells and blood plasma, osmoregulation),
solutes,
temp,
O2/Co2,
heart rate,
input/output
What is a Negative feedback mechanism?
A change in a variable under homeostatic control, triggers a response that opposes the change
sensor:
detects environmental conditions
ex. temp: nerve endings in skin
Integrator:
analyzes signal from sensor, compares conditions to the set point and activated an appropriate effector
ex. brain, hypothalamus
Effector:
causes a physiological change that opposes the deviation from the set point
ex. skeletal muscle, sweat glands
stimulus:
something that causes something else to happen, develop, or become more active
Negative feedback mechanisms work to
reestablish homeostasis
Positive feedback mechanisms are
change in variable under homeostatic control triggers a response that amplifies the change
good for achieving an outcome once
Positive feedback mechanisms push a system
away from homeostasis (produces more and more)
Amplifies the change
not homeostatic
Thermoregulation is
regulating the internal body temperature
Temperature has a huge impact on
energy budgets
_________ has a huge impact on
energy budgets
Temperature
Ambient temperature (Ta)
Body temperature (Tb)
What’s the same and what’s different for ectotherms and endotherms?
for ectotherms the ta and Tb are the same
for endotherms the ta and Tb are different (bc endotherms create their own heat)
heat is generated by
metabolism
heat can be exchanged with the environment by
conduction, convection, evaporation, and radiation
Endotherms use the heat made by
metabolism for ______
thermoregulation
Ectotherms let the heat generated by metabolism ________
dissipate into the environment
Body heat can be regulated by
changing the rate of heat gain and loss
Rate of heat exchange is called
conductance
Large organisms have ______ due to _______
lower conductance (rate of heat exchange)
smaller SA:V ratios
Small organisms have ________ due to ______
higher conductance (rate of heat exchange)
larger SA:V ratios
homeotherm:
maintains a constant body temp (Tb) independent of ambient temperature (Ta),
can be human or earthworm.
very stable temperature
most endotherms are homotherms
Heterotherms:
(Tb) fluctuates with (Ta).
mostly ectotherms, but some can be endotherms
ex. Freshwater fish whose (Tb) changes with seasonal changes in the water temperature (Ta).
Endotherms:
uses metabolism to generate body heat (internal heat generation)