T8 Thermoregulation Flashcards
Homeostasis
regulation of internal environment in face of changes in external environment
Parameters of homeostasis
pH, water (volume and pressure of cells and blood plasma, osmoregulation), solutes, temperature, O2/CO2, heart rate.
Negative feedback mechanisms
change in a variable under homeostatic control triggers response that opposes change
Sensor
detects environmental conditions
Integrator
analyzes signal from sensor, compares conditions to set point and activates appropriate effector
Effector
causes a physiological change that opposes the deviation from the set pont
Positive feedback mechanisms
change in a variable under homeostatic control triggers a response that amplifies change
Thermo regulation .
regulating internal body temp
Ambient Temperature
Ta
Body temperature
Tb
Heat generated by metabolism
body heat
Heat can be exchanged with environments by conduction, convection, evaporation and radiation
body heat
Have lower conductance due to Smaller SA/V ratios
Large organisms
Homeotherm
maintains constant body temperature (Tb) independent of ambient temperature
Heterotherm
Tb fluctuates
Endotherm
uses metabolism to generate body heat (internal heat source)
Ectotherm
acquires body heat from environment (external heat sources)
Thermal Neutral Zone
temperature range around an animal where it can maintain its normal body temperature without using extra energy.
Below TNZ (hypothermy)
Shivering, vasoconstriction, piloerection, decreasing surface area, decreasing exposure (huddling/burrowing)