topic 8

Question 1

what is homeostasis?

Answer 1

The regulation of an internal environment in the face of changes in the external environment

Question 2

what is a negative feedback system?

Answer 2

A change in a variable under homeostatic control triggers a response that opposes the change

Question 3

what is a sensor?

Answer 3

detects environmental conditions

Question 4

what is an integrator?

Answer 4

Analyses signal from sensor, compares conditions to the set point and activates an appropriate effector

Question 5

what is an effector?

Answer 5

Causes a physiological change that opposes the deviation from the set
point

Question 6

how does a sensor work for temperature regulation?

Answer 6

temp detection nerves in skin

Question 7

what is the integrator for temperature regulation?

Answer 7

the hypothalamus

Question 8

what are the effectors for temperature regulation?

Answer 8

muscle tissue, vasculature, sweat glands

Question 9

what is a positive feedback system?

Answer 9

A change in a variable under homeostatic control triggers a response that amplifies the change

Question 10

what is thermoregulation?

Answer 10

Regulating the internal body temperature

Question 11

what is the rate of heat exchanged called?

Answer 11

conductance

Question 12

how is body heat generated?

Answer 12

by metabolism

Question 13

what are the ways that heat can be exchanged with the environment?

Answer 13

conduction, convection, evaporation and radiation

Question 14

how is body heat regulated?

Answer 14

by changing the rate of heat gain and loss

Question 15

what is a homeotherm?

Answer 15

maintains “constant” body temperature
independent of ambient temperature

Question 16

what is a heterotherm?

Answer 16

body temperature fluctuates with ambient temperature

Question 17

how does an ectotherm generate heat?

Answer 17

acquires body heat from the environment
generate heat from metabolism but they don’t keep it
external heat generation

Question 18

how do endotherms generate body heat?

Answer 18

uses metabolism to generate heat
internal heat generation

Question 19

what is ambient temperature?

Answer 19

the average temperature of the environment

Question 20

where does thermoregulation occur?

Answer 20

above and below the thermal neutral zone

Question 21

what is hypothermy?

Answer 21

temperature below the TNZ

Question 22

what are symptoms of hypothermy?

Answer 22

Shivering, vasoconstriction, piloerection, decreasing surface area, decreasing exposure (huddling/burrowing)

Question 23

what is hyperthermy?

Answer 23

temperature above the TNZ

Question 24

what are symptoms of hyperthermy?

Answer 24

Panting, vasodilation, sweating, increasing surface area, decreasing exposure (to sun)

Question 25

what is low conduction an adaptation for?

Answer 25

heat retention

Question 26

what is high conduction an adaptation for?

Answer 26

heat loss

Question 27

what is behavioural regulation of conductance?

Answer 27

Moving to optimize heat exchange with the environment to attain an ideal body temperature

Question 28

what are the 4 ways of behavioural regulation of conductance?

Answer 28

migration grouping exposure dormancy

Question 29

what is exposure?

Answer 29

movement into or out of the sun/wind increasing/decreasing surface area

Question 30

what is grouping?

Answer 30

huddling together to share radiation

Question 31

what is daily torpor?

Answer 31

A short (6-8 hours) reduction in activity

Question 32

what are characteristics of daily torpor?

Answer 32

10C drop in Tb and a lower MR Reduce spending energy to stay warm (especially when food is scarce in winter)

Question 33

what is hibernation?

Answer 33

a long cycle of a 2-week reduction in activity before 1-2 days of being awake

Question 34

what are the characteristics of hibernation?

Answer 34

Tb regulated close to Ta Massive reduction in MR Requires massive heat generation for arousal

Question 35

what are the 2 types of dormancy?

Answer 35

hibernation daily torpor

Question 36

if bears dont hibernate what do they do?

Answer 36

they winter sleep 2-3 days 10 degrees lower than Tb

Question 37

why don't bears need to hibernate?

Answer 37

small SA/V, lots of insulation (fat/fur), but food is scarce, so they sleep and burn fat

Question 38

what is migration?

Answer 38

Complete avoidance of poor environmental conditions

Question 39

what is physiological regulation of conductance?

Answer 39

Making physiological adjustments to optimize heat exchange with the environment to attain an ideal body temperature

Question 40

what are the 7 methods of physiological conductance regulation?

Answer 40

Acclimation Blood Flow Insulation Fur Length and Colour Change Sweating/panting Cryoprotectants Shivering Thermogenesis Non-shivering Thermogenesis

Question 41

what is membrane acclimation?

Answer 41

membrane viscosity is affected by temperature

Question 42

what is vasoconstriction?

Answer 42

Decreases conductance with environment

Question 43

when do endotherms use vasoconstriction?

Answer 43

when cold to retain heat

Question 44

when do ectotherms use vasoconstriction?

Answer 44

when hot to retain heat

Question 45

what is vasodilation?

Answer 45

increases conductance with environment

Question 46

when do endotherms use vasodilation?

Answer 46

when hot to release heat

Question 47

when do ectotherms use vasodilation?

Answer 47

when cold to increase heat gained from environment

Question 48

what types of insolation are there?

Answer 48

internal external piloerection

Question 49

what is internal insolation?

Answer 49

fat/blubber internal insulation layer to slow rate of heat transfer

Question 50

what is external insolation?

Answer 50

fur/feathers external insulation layer to slow rate of heat transfer

Question 51

what is piloerection?

Answer 51

the “fluffing” of fur/feathers decreasing the rate of heat transfer by increasing thickness of insulation layer

Question 52

how does dark fur affect body temperature?

Answer 52

absorbs light generates heat outside of insulation layer easily lost to the environment

Question 53

how does light fur affect body temperature?

Answer 53

allows light to reach skin generates heat inside the isolation layer

Question 54

what is sweating/panting?

Answer 54

heat loss due to evaporation

Question 55

what is a cryoprotectant?

Answer 55

glucose/glycerol molecules produced to lower freezing point allow ice to form in extracellular spaces but not internally

Question 56

what are ice nucleating agents?

Answer 56

like antifreeze prevents ice formation

Question 57

what is shivering thermogenesis?

Answer 57

Simultaneous action of antagonistic muscles generate heat without causing movement

Question 58

what is non-shivering thermogenesis?

Answer 58

Special fat tissue (brown fat) that is loaded with “special” mitochondria Instead of using PMF for ATP production, its used to generate “heat” Used by organisms to raise Tb