Thermoregulation

Question 1

Why do we need thermoregulation

Answer 1

enzymes denature if too hot. water freezes if too cold

0-40C is ideal

Question 2

Homeotherms

Answer 2

Temperature regulators. Maintain a constant internal body temperature.

Mammals birds insects bees

Question 3

Poikilotherms

Answer 3

Temperature conformers. Temeperature determined by external enviornment
reptiles, amphibians, and fish

Question 4

Body Temperature impacted by

Answer 4

heat from environment
heat lost to environment
heat generated as a metabolic by product

Question 5

Heat in must

Answer 5

=heat out for homeostasis

Question 6

Endotherms

Answer 6

gain most of their heat through their own metabolism

Question 7

ectotherms

Answer 7

gain most of their heat from external sources

Question 8

Homeotherms are primarily

Answer 8

endotherms. Producing their own heat from metabolism

Question 9

Thermoneutral Zone TNZ

Answer 9

homeotherm metabolic rate is lowest here
temperature range over which organisms function without stress
horizontal part of graph

Question 10

Homeotherms outside of TNZ

Answer 10

increase metabolic rate if too hot or too cold

outside TNZ, increase metabolic rate to compensate for temp difference

Question 11

Homeotherm is cold

Answer 11

losing heat to the enviornment
ramp up metabolism to create more heat

shivers- contract antagonist muscles
non shivering thermogenesis
vasoconstriction

Question 12

homeotherm is warm

Answer 12

needs to lose excess heat, takes energy to get rid of heat
end up losing more heat by spending a little extra on metabolism

sweats- evaporative cooling
bathing
panting
vasodilation

Question 13

poikilotherm metabolic activity

Answer 13

body temp matches outside, metabolic rate does as well, correlates with temperature. increases with temp increase

Question 14

non shivering thermogenesis

Answer 14

brown fat cells stop producing ATP- most of food goes to heat generation

Question 15

homeotherm metabolism vs. poikioltherm

Answer 15

way higher (5-10) in homeotherms
energy expensive to be a homeotherm

Question 16

homeotherm vs poikilotherm

Answer 16

homeotherm- need lots of food, wider variety of environments, energetically expensive, deal well with cold snaps
poikilotherm- constrained in environment temperature range, save energy, dont eat as often, sluggish in cold temps

Question 17

enviornmental heat transform 4 mechanisms

Answer 17

radiation- gain from radioactive waves
convection- air or liquid flow
conduction- physical contact with objects
evaporation- water evaporates from skin

Question 18

Fourier’s Law

Answer 18

Q=KA DELTA T/d

Question 19

parts of fourier law

Answer 19

Q- amount of heat transferred
A- heat transfer area
K- thermal conductivity of material
Delta T- temperature difference for transfer
d- material thickness

All increase temperature except thickness. less thick, increases heat transfer

large area, large heat transfer

Question 20

BEhavioral thermoregulation

Answer 20

both poikilotherms and homeotherms do this
move in and out of sun
optimize temp by behavior

ectotherms primarily rely on this to adjust body temp

Question 21

Burrows

Answer 21

behavioral regulation for an ectotherm of temp

Question 22

Anatomic adaptations for thermoregulation

Answer 22

large SA to Volume ratio loses heat to environment, want a low ratio in the cold; high ratio in the heat

thermal conductvity/thickness of insulation

hair feathers and adipose tissue for insulation

Question 23

arctic animals

Answer 23

compact body to decrease SA to V ratio and thus heat lost to enviornment
layers of fat and blubber for insulation

Question 24

Circulatory adaptations for thermoregulation

Answer 24

vasoconstriction- decrease blood diamter for cold environment. Reduces SA and thus heat loss. Diverts blood to body’s core–> frostbite

Vasodilation- blood vessels increase in hot external conditions with increased SA

used by both poikilotherms and homeotherms

Question 25

blood near the surface

Answer 25

will exchange heat with the environment

Question 26

What do we do if blood is too cool due to the enviornment

Answer 26

countercurrent exchange

Question 27

concurrent exchange

Answer 27

blood vessels flow in the same direction. high initial heat transfer, but reaches equilibrium with no net heat flow.

Question 28

countercurrent exchange

Answer 28

``` maximum transfer of heat one going to body with warm blood one going to heart with cold blood flow in opposite directions so warm blood can mix into the cold blood, increasing body temp gradient maintained longer ```

Question 29

countercurrent heat exchange examples

Answer 29

tuna and great white sharks cold blood from the gills and warm blood from the body's core. birds and marine mammals with feet in cold water

Question 30

large body extremeties

Answer 30

veins located here so heat from arteries can be transferred to veins and lose heat to environment tropical bird bills

Question 31

thermostat of the body

Answer 31

hypothalamus