1. Temperature regulation HBS3A

2. Homeostasis Maintenance of constant internal environment This involves continually replacing substances as they are used up (eg glucose, oxygen) or continually removing substances as they build up (eg wastes)

3. Negative feedback systems Stimulus Receptor Modulator Effector Response Negative feedback

4. Negative feedback systems Stimulus change in conditions Receptor detects the change Modulator decides what to do about the change Effector part of the body that carries out the response Response change in activity Negative feedback response alters the stimulus in the opposite direction

5. Metabolism and temperature Metabolism refers to all reactions occurring in the body Metabolic rate refers to the amount or speed of reactions in the body. It can be measured by measuring temperature, rate of oxygen consumption or rate of carbon dioxide production Reactions produce waste heat. The more reactions that occur, the greater the temperature Reactions rely on enzymes

6. Enzyme activity and temperature Enzyme activity Temperature

7. Metabolic rate and temperature As temperature increases, metabolic rate increases As metabolic rate increases, temperature increases

8. Body temperature Poikilotherms have changing body temperatures - the same as their environment eg fish, amphibians, reptiles Homeotherms have constant body temperatures regardless of the environment eg birds, mammals Ectotherms control body temperature by behaviour eg fish, amphibians, reptiles Endotherms control body temperature by internal mechanisms eg birds, mammals Humans are endotherms and homeotherms Environmental temperature Body temperature Metabolic rate Environmental temperature Poikilotherms Endotherms Homeotherms Ectotherms

9. Heat production Heat can be produced by: Metabolism eg Movement Voluntary eg Involuntary eg

10. Heat production Heat can be produced by: Metabolism eg respiration Movement Voluntary eg exercise Involuntary eg shivering

11. Heat loss or gain Occurs from body surfaces Uses the processes of: Radiation Conduction Convection Evaporation

12. Radiation Loss without contact Can be increased by Can be decreased by

13. Radiation Loss without contact Can be increased by Increasing surface area exposure eg basking, vasodilation, taking off clothes Can be decreased by Decreasing surface area exposure eg huddling, vasoconstriction, putting on clothes

14. Conduction Loss by contact Can be increased by Can be decreased by

15. Conduction Loss by contact Can be increased by Increasing surface area exposure eg swimming Can be decreased by Decreasing surface area exposure eg increased insulation (eg blubber)

16. Convection Loss by air movements Can be increased by Can be decreased by

17. Convection Loss by air movements Can be increased by Increasing surface area exposure to wind eg sprawling, taking off clothes, turning on fan Can be decreased by Decreasing surface area exposure to wind eg huddling, putting on clothes

18. Evaporation Loss of heat due to liquid turning to gas Can be increased by Can be decreased by

19. Evaporation Loss of heat due to liquid turning to gas Can be increased by sweating, panting or wetting skin Can be decreased by reducing sweating or panting, keeping surface dry or covered with clothing

20. Control of body temperature Control of heat production Increasing or decreasing metabolic activity or movement (shivering or exercise) Control of heat loss Increasing or decreasing loss of heat from external or respiratory surfaces

21. Temperature regulation Stimulus Negative feedbackReceptor ResponseModulator Effector Increased temperature

22. Temperature regulation Stimulus Negative feedbackReceptor ResponseModulator Effector Increased temperature Thermoreceptors Hypothalamus in brain Sweat glands Increased sweating Cool down

23. Temperature regulation 2 Stimulus Negative feedbackReceptor ResponseModulator Effector Cold

24. Temperature regulation 2 Stimulus Negative feedbackReceptor ResponseModulator Effector Thermoreceptors Hypothalamus in brain Cold Muscles Shivering Warm up

25. Structural adaptations Bare skin or reduced fur Endomorphic body shape Counter current exchange Ectomorphic body shape

26. Physiological adaptations Sweating Increased breathing rate Increased heart rate Vasodilation Vasoconstriction Hunching Shivering

27. Behavioural adaptations Use a fan Immersing in cold water Seeking shade Resting during heat Reduce clothes Hot bath Use a heater Add clothes