Topic 8: Thermoregulation Flashcards
Homeostasis
regulation of internal environment in the face of changes in the external environment (dynamic process)
What parameters must organisms control for homeostasis?
- pH
- temperature
- O2/Co2
- heart rate
- solutes
- water (volume and pressure of cells & blood plasma)
- osmoregulation
Negative Feedback Mechanisms
a change in a variable under homeostatic control triggers a response that OPPOSES the change
Sensor
detects environmental conditions
Integrator
analyzes sign from signal; compares conditions to the set point & activates effector
Effector
causes a physiological change that opposes the deviation from the set point
Role of sensor in temperature regulation
detects temp. in skin
What is the integrator in temperature regulation
hypothalamus
What is the effector in temperature regulation?
muscle tissue, vasculature, sweat glands
Positive Feedback Mechanisms
change in a variable under homeostatic control triggers a response that AMPLIFIES the change
Thermoregulation
regulating internal body temperature
- this has huge impact on energy budgets
Ta
ambient temperature
Tb
body temperature
Body heat
generated by metabolism
can be exchanged with environment
regulated by changing rate of heat gain/loss
The rate of heat exchange is called
conductance
4 ways heat can be exchanged with the environment is:
conduction
convection
evaporation
radiation
What is the adaptation for heat retention?
low conductance
What is the adaptation for heat loss?
high conductance
How do ectotherms primarily regulate Tb?
using behaviour
When temperature rises above thermal neutral zone, homeothermic endotherms risk entering state of _______________
hyperthermia
Animals _______ have to spend energy to maintain body temperature during hibernation
do
____________ have a broader range of temperatures
endotherms
Homeotherms
maintain constant Tb independant of Ta