1. Comparative Vertebrate Physiology
Temperature regulation

2. Temperature regulation
O2 consumption depends on temperature

3. Heat production At rest During exercise 70 - 80% from organs
% from skeletal muscle
During exercise
Skeletal muscle produces X more heat than rest of body

4. Control of heat
Metabolism plus heat transfer

5. Heat transfer Conduction Convection
Transfer of heat from physical contact
Convection
Transfer of heat by warming a layer of air or water. Replacement of layer increases heat transfer

6. Heat transfer Radiation Evaporation
Transfer of infrared rays (thermal heat)
50% of heat transfer
Evaporation
Liquid turning into a gas transfers heat
Lungs and skin

7. Thermal strategies Based on stability of body temperature
Homeotherms (birds, mammals)
Poikilotherms (fish, amphibians, reptiles)

8. Thermal strategies Based on ability to produce heat
Endotherms (birds and mammals)
Ectotherms (fish, amphibians, reptiles)

9. Thermal strategy summary

10. Thermal strategy
Heterothermy
Temporal (monotremes)
Regional (fish)

11. Heat production 1. Vasoconstriction of cutaneous vessels
Restrict blood flow to the core
Short vs. long term (frostbite)

12. Heat production 2. Increase metabolic rate 3. Thyroxine release
Norepinephrine from sympathetic fibers
3. Thyroxine release

13. Heat production 4. Shivering 5. Behavioral As a last resort
Involuntary muscle contraction
5. Behavioral
Huddling

14. Heat loss 1. Vasodilation 2. Perspiration 3. Behavior
Increase loss via heat transfer
2. Perspiration
If dry it’s efficient, if not it’s inefficient
3. Behavior