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Biology Of Mammals > Physiology > Flashcards

Flashcards in Physiology Deck (57):
1

How can hair reduce conductance?

Piloerection and seasonal moults

1

What is wrong with sweating?

Water and salt loss

3

What is Bergmann's rule?

Body size increases with latitude/temperature

3

What is temporal heterothemy?

Times of the year/day where they can afford to be cooler to reduce energy budget

4

What is the lethal loss of water?

More than 20%

5

What is active cooling?

Energy expended in cooling

5

What is daily torpor?

Body temperature drops during the day

6

What is the formula for the cost of homeothermy?

VO2 = C(Tb - Ta)

6

How can ears aid evaporation?

Vascularisation, vasodilation, flapping

7

What is C?

conductance - rate of heat loss from body to the environment

8

What is interesting about Coyote BMR?

79% in desert. 126% in Alaska

9

What is endothermy?

The ability to maintain/generate heat through a combination of internal metabolic activity and physiological regulation

10

What are the costs of not thermoregulating?

Hyperthermia and Hypothermia

10

How does feeding at night conserve water in oryx?

Parched plants absorb moisture from the air. More water in plants at night

11

What factors determine conductance?

Insulation, body size and shape.

12

What is region heterothermy?

Parts of the body maintained at cooler temperature to reduce the cost.

13

How does migration reduce energy expenditure?

Minimised Tb-Ta

14

Which animals retain body heat longer?

Larger body size

14

How does body shape affect heat loss and energy costs?

Long thin animals = low surface area: volume ratio

15

What is Allen's Rule?

Animals living in more extreme environmental conditions have smaller limbs

17

What is Ta?

Ambient temperature

18

How is an oryx heat and drought tolerant?

Relies on metabolic water, seeks shade

19

What are the physiological consequences of fossorial living?

Lower Basal metabolic rates. Lower respiratory and heart rates

21

What is homeothermy?

Heat isn't generated, temperature is just maintained

22

What are the costs of thermoregulation?

High energy demand

23

What is basal metabolic rate?

Minimum metabolic rate required to maintain resting function in thermal neutral zone

23

What is passive cooling?

Basing/shading. Conduction to draw heat off

24

What is the lower critical temperature?

Point below which the balance between metabolic heat production and heat loss cannot be maintained

24

Why is sharing a hibernacula good?

Cost free benefit to share

25

What is evaporative cooling?

Evaporation of fluid from the body surface: sweating, saliva, urination

26

What do methatheria and eutheria BMR vary?

Methatheria have a lower BMR. Eutheria is higher from the selection for high reproductive rates

27

How is a camel heat and drought tolerant?

Thermal interia, rapid heat loss at night. Interstitial intracellular fluid

29

What is heterothermy?

Varying body temperatures

31

How do food habitats affect BMR?

Foliovores, soil/litter, ant/termite have low Small/aquatic carnivores have high

32

What is the upper critical temperature?

Point above which metabolic work is needed in order to dissipate heat by evaporative cooling and maintain constant temperature

33

Why homeothermy evolve?

Selective pressure for sustained activity and reduced body size

35

What is the principle function of hair?

Insulation

36

Which does larger body size mean great thermal interia?

Less energy is required for cooling and heating

36

How can water be conserved?

Kidney, gut, lactation, diet, behaviour, respriation

37

What is thermal inertia?

Degree of slowness with which the temperature of a body approaches that of its surrounding

37

How can mammals display heterothermy?

Regionally (within the body), temporally (over time)

39

What is thermal neutral zone?

When little or no metabolic energy is expended on temperature

40

How does a kangaroo rat survive?

Reliant on metabolic water from seeds. Nocturnal. Concentrated milk

41

What is the thermal neutral zone of most mammals?

36-38

42

What is metabolic water?

By-product of aerobic metabolism

44

What are the benefits of homeothermy?

Homeostasis, continouous activity

45

How do animals conserve energy?

Minimise conductance through insulation

47

What is hibernacula?

Place of abode in which creature hibernates

48

What is sub-cutaneous fat?

Layer of fat found just beneath the skin, insulation and energy

49

How does body size effect heat loss and energetic costs?

Larger animals have lower Area: volume ratio

50

What is monotremes body temperature?

lower, just above 30

51

Which is better panting or sweating?

Panting

53

How long do edible dormice hibernate for?

7 months

54

What is active heating?

Energy expended in generating heat

55

How do fur seals lose heat?

Finning - flapping fins which sweat to increase evaporative cooling

56

What is Tb?

Variation in body temperature

57

What is seasonal torpor?

Prolonged drop in body temperature triggered by food variation, decline in day length, low temperatures