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8.1 Thermoregulation — Test 1
Q1. Animals that maintain a constant body temperature regardless of their surroundings are called:✓ Homeotherms (endotherms)
Q2. Cold-blooded animals whose body temperature varies with the environment are called:✓ Poikilotherms (ectotherms)
Q3. The brain centre that acts as the body's thermostat is the:✓ Hypothalamus
Q4. When the body becomes too hot, heat loss is increased by:✓ Vasodilation of skin vessels and sweating
Q5. When the body becomes too cold, heat is generated by:✓ Shivering (and non-shivering thermogenesis)
Q6. Heat production in brown adipose tissue (non-shivering thermogenesis) depends on:✓ Uncoupling protein (thermogenin) in mitochondria
Q7. In cold conditions, the constriction of skin blood vessels helps the body by:✓ Reducing heat loss from the skin surface
Q8. Acclimatisation refers to:✓ Gradual physiological adjustment to a changed environment
Q9. A fever (raised body temperature) is caused by:✓ A resetting of the hypothalamic set point by pyrogens
Q10. The main way humans lose heat in a hot, dry environment is by:✓ Evaporation of sweat
Q11. The comfort (thermoneutral) zone is the range of environmental temperature in which:✓ The body maintains temperature with minimal energy expenditure
Q12. Heterotherms are animals that:✓ Can vary between regulating and not regulating their temperature
Q13. Counter-current heat exchange in the limbs of some animals helps to:✓ Conserve core heat by warming returning venous blood
Q14. Animals in cold climates tend to have smaller extremities (ears, limbs), an observation summarised by:✓ Allen's rule
8.1 Thermoregulation — Test 2
Q15. Larger body size in colder climates (reducing surface-area-to-volume ratio) is described by:✓ Bergmann's rule
Q16. Hibernation helps some mammals survive winter by:✓ Lowering body temperature and metabolic rate to save energy
Q17. Animals that generate their own body heat to maintain a constant temperature are:✓ Endotherms
Q18. Reptiles bask in the sun because they are:✓ Ectotherms relying on external heat
Q19. The body's thermostat, which detects and corrects temperature changes, is the:✓ Hypothalamus
Q20. When overheated, the body increases heat loss by:✓ Sweating and skin vasodilation
Q21. When cold, the body conserves and generates heat by:✓ Shivering and skin vasoconstriction
Q22. Heat generated without shivering, important in newborns, comes mainly from:✓ Brown adipose tissue
Q23. A fever results from:✓ Resetting the hypothalamic set point higher by pyrogens
Q24. Acclimatisation to a cold climate over weeks is:✓ A reversible physiological adjustment
Q25. Counter-current heat exchange in the limbs helps to:✓ Conserve core body heat
Q26. In a hot, humid environment, cooling by sweating becomes less effective because:✓ High humidity slows evaporation of sweat
Q27. Bergmann's rule states that, within a species, animals in colder climates tend to be:✓ Larger in body size
Q28. Hibernation conserves energy in winter by:✓ Lowering body temperature and metabolic rate