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Flashcards in Homeostasis Deck (49):
1

What best describes the limits to life on earth?

the freezing point of water and the temperature when proteins denature (0 - 40 degrees Celsius)

2

If the Q10 of animal's metabolic rate is 2, then --

the animal consumes 1/2 as much oxygen per hour at 20 degrees then 30 degrees Celsius

3

What statement about brown fat is true?

it produces heat without producing much ATP

4

What's the most important and most general characteristic of endotherms adapted to cold climates compared with endotherms adapted to warm climate?

greater insulation

5

what would cause a decrease in the hypothalamic temperature set point for metabolic heat production?

taking an aspirin when you have a fever

6

Because of their -- endotherms expend more energy (thus more heat) just to maintain the ion concentration gradients across their membranes

leaky membranes

7

sum of total energy expenditures in body at rest

metabolic rates

8

True or False: behavioral thermoregulation is exclusive to ectotherms

False

9

energy budget

heat in = heat out
metabolism + R in = R out + convection + conduction + evaporation

10

surface temperature can be controlled by altering the -- to the skin

flow of blood

11

mammals have specialized blood vessels for transporting heat to --

hairless surfaces of the skin

12

cold fish: heat that blood picks up from metabolically active muscles is -- to water flowing across its gills

lost

13

hot fish: heat rows from warm blood to cold blood by --

conduction

14

the internal body temperature of a hot fish is -- than water temperature

greater

15

for hot fish, 10 degree Celsius increase in muscle temperature, increases fish sustainable power -->

faster

16

True or False: Some ectotherms regulate metabolic heat production

true (insects - scarab beetle, worker bees)

17

How to determine metabolic rate by measuring what?

oxygen consumption or carbon dioxide production

18

within a narrow range of environmental temperature, the metabolic rates of endotherms are at low levels and independent of temperature

thermoneutral zone

19

resting animal is consuming enough energy to carry out its minimal body functions

BMR

20

BMR of elephant is -- than the BMR of mouse

greater

21

BMR per gram of tissue increases as an animal gets --

smaller

22

Endotherms respond to cold by producing -- and adapt to cold by reducing --

heat, heat loss

23

birds only use -- heat production

shivering

24

non shivering heat production occurs in --

brown fat cells

25

thermogenin is found in

brown fat cells

26

brown fats are -- in some adults

small

27

-- can be found in animals acclimatized to cold or hibernation

brown fat cells

28

most common and important means of decreasing heat loss

increasing thermal insulation

29

other ways to decrease heat loss include

decrease blood flow to skin (constriction of blood vessels in skin) and countercurrent heat exchange

30

for exercising animals, overheating can occur even at

low environmental temperatures

31

sweating and panting are -- process that require expending metabolic energy (generate heat in the process of dissipating heat)

active

32

slight cooling of hypothalamus

constriction of skin blood vessels

33

stronger cooling of hypothalamus

increases metabolic heat production

34

heated hypothalamus

metabolic rate and body temperature falls and favors heat loss

35

hypothalamus itself is a major -- that generates set points for thermoregulation responses

feedback signal

36

change in skin temperature is a -- that shifts hypothalamic set point

feedforward information

37

hypothalamic set point -- when awake or active

increases

38

set point for metabolic heat production is -- when skin is cold

higher

39

a rise in body temperature in response to pyrogens

fever

40

pyrogens like foreign proteins produced by bacteria or virus

exogenous

41

pyrogens like substances produced by immune cells in response to infection

endogenous

42

during a fever, the body temperature rises until you match --

new set point

43

aspirin -- set point to normal so you feel --

lowers, hot

44

some animals conserve energy by turning --

down thermostat

45

below normal body temperature

hypothermia

46

some animals undergo -- to survive periods of cold and food scarcity

regulated hypothermia

47

regulated hypothermia can last for

days or even weeks

48

some small endotherms with high metabolic rates such as hummingbirds can survive without food (normally inactive)

daily torpor

49

body temperature falls close to ambient temperature (1/15 of BMR)

hibernation