Physiology Flashcards by Rebekah Trehern

How can hair reduce conductance?

Piloerection and seasonal moults

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What is wrong with sweating?

Water and salt loss

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What is Bergmann’s rule?

Body size increases with latitude/temperature

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What is temporal heterothemy?

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

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What is the lethal loss of water?

More than 20%

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What is active cooling?

Energy expended in cooling

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What is daily torpor?

Body temperature drops during the day

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What is the formula for the cost of homeothermy?

VO2 = C(Tb - Ta)

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How can ears aid evaporation?

Vascularisation, vasodilation, flapping

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What is C?

conductance - rate of heat loss from body to the environment

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What is interesting about Coyote BMR?

79% in desert. 126% in Alaska

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What is endothermy?

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

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What are the costs of not thermoregulating?

Hyperthermia and Hypothermia

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How does feeding at night conserve water in oryx?

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

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What factors determine conductance?

Insulation, body size and shape.

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What is region heterothermy?

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

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How does migration reduce energy expenditure?

Minimised Tb-Ta

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Which animals retain body heat longer?

Larger body size

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How does body shape affect heat loss and energy costs?

Long thin animals = low surface area: volume ratio

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What is Allen’s Rule?

Animals living in more extreme environmental conditions have smaller limbs

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What is Ta?

Ambient temperature

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How is an oryx heat and drought tolerant?

Relies on metabolic water, seeks shade

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What are the physiological consequences of fossorial living?

Lower Basal metabolic rates. Lower respiratory and heart rates

What is homeothermy?

Heat isn’t generated, temperature is just maintained

What are the costs of thermoregulation?

High energy demand

What is basal metabolic rate?

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

What is passive cooling?

Basing/shading. Conduction to draw heat off

What is the lower critical temperature?

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

Why is sharing a hibernacula good?

Cost free benefit to share

What is evaporative cooling?

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

What do methatheria and eutheria BMR vary?

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

How is a camel heat and drought tolerant?

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

What is heterothermy?

Varying body temperatures

How do food habitats affect BMR?

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

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

Why homeothermy evolve?

Selective pressure for sustained activity and reduced body size

What is the principle function of hair?

Insulation

Which does larger body size mean great thermal interia?

Less energy is required for cooling and heating

How can water be conserved?

Kidney, gut, lactation, diet, behaviour, respriation

What is thermal inertia?

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

How can mammals display heterothermy?

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

What is thermal neutral zone?

When little or no metabolic energy is expended on temperature

How does a kangaroo rat survive?

Reliant on metabolic water from seeds. Nocturnal. Concentrated milk

What is the thermal neutral zone of most mammals?

36-38

What is metabolic water?

By-product of aerobic metabolism

What are the benefits of homeothermy?

Homeostasis, continouous activity

How do animals conserve energy?

Minimise conductance through insulation

What is hibernacula?

Place of abode in which creature hibernates

What is sub-cutaneous fat?

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

How does body size effect heat loss and energetic costs?

Larger animals have lower Area: volume ratio

What is monotremes body temperature?

lower, just above 30

Which is better panting or sweating?

Panting

How long do edible dormice hibernate for?

7 months

What is active heating?

Energy expended in generating heat

How do fur seals lose heat?

Finning - flapping fins which sweat to increase evaporative cooling

What is Tb?

Variation in body temperature

What is seasonal torpor?

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