thermoregulation

Question 1

how is homeostasis maintained?

Answer 1

via feedback mechanisms

Question 2

why is temp important

Answer 2

biological sensitivity (enzymes and lipids)
metabolic rate depends on temp

Question 3

describe Q10 effect

Answer 3

 Measures increase in rate of biochemical reactions/processes with temperature, at 10*C increments
 Most biological chemistry increases somewhere between the square (eg. Q10=2) and the cube (eg. Q10=2) of the temperature

Question 4

define: poikilotherm vs homeotherm

Answer 4

animal with varying/stable body temperature

Question 5

define: endotherm vs ectotherm

Answer 5

animal whose primary source of body heat is metabolic/environmental

Question 6

why do endotherms have higher metabolism and hence more metabolic heat than ectotherms?

Answer 6

have leakier membranes, causing unnecessary metabolic work that produces energy
-eg. maintaining proton gradients across mitochondrial membranes
maintaining ion conc gradients

Question 7

describe metabolic rate of ectotherms

Answer 7

increases following Q10 curve initially until it reaches resting metabolic rate; then rate of increase in met slows down

Question 8

describe metabolic arte of endotherms

Answer 8

Thermal neutral zone
 Has the lowest metabolic rate (ie. Basal metabolic rate)
 No extra work required to stay warm or cool
 Differs between species
o Metabolic rate increases with increased/decreased temp

Question 9

describe how brown adipose tissue works

Answer 9

 When active, mitochondria’s ATP synthase turn off which increases heat

Question 10

describe how hypothalamus works

Answer 10

 External temp decreases/increases
 Hypothalamus activates heating/cooling mechanisms
• Sweat glands, blood vessels contract/dilate
 Body temp decreases

Question 11

describe countercurrent heat exchange

Answer 11

o Artery going down adjacent to vein going up
o Artery has higher temp than vein at all points of contact, and transfers heat to vein
o Can be found in extremities – eg. dolphin fins, ducks foot etc

Question 12

describe 2 types of sweat glands

Answer 12

Atrichial (primates, pads of cats and dogs)

Epitrichial (associated with hair – other mammals)

Question 13

describe daily torpor

Answer 13

daily hibernation

Question 14

define evaporation

Answer 14

removal of heat when liquid evaporates

Question 15

in terms of energy, evaporation is

Answer 15

endothermic but exergonic

Question 16

define: radiation

Answer 16

transfer of heat between two non touching objects

Question 17

define: convection

Answer 17

transfer of heat by movement of air/liquid past a surface

Question 18

define: conduction

Answer 18

transfer of heat between two touching objects

Question 19

difference between conductor and insulator?

Answer 19

o Conductors transfer heat through them easily; whereas insulators do not

Question 20

3 examples of conductors in decreasing order?

Answer 20

water/muscle -> fat -> fur/wood

Question 21

describe effect of mass on bmr and diet

Answer 21

 Bigger total mass of animal  bigger BMR  eat more

 Smaller total mass of animal  bigger BMR per unit body mass eat more per unit mass