Thermoregulation Flashcards
What happens when molecules get hotter
They move around faster. so chemical reactions speed up
What happens if temperature becomes too high
Temperature can cause enzymes to denature
What are the 2 ways animals regulate their body temp
Ectothermy and endothermy
What are ectotherms
Animals that rely on external sources of heat to regulate their body temperature (cold blooded)
What are endotherms
Animals that use heat from metabolic reactions to maintain their body temperature
What are changes in temperature detected by
Temperature receptors in the thermoregulatory centre of the hypothalamus
What occurs if the temperature receptors detect a change
Causes nervous and hormonal systems to send signals to effectors
Where else are temperature receptors found
In the skin which also contact hypothalamus
What is the purpose of temperature receptors in the skin
They warn the hypothalamus of oncoming changes to temperature before the blood temperature has changed
How do ectotherms regulate their temperature
By using their behaviour
What does an ectotherm do if it is too cold
- Move into the sun
- Expose more surface area to the sun
- Move towards warm surfaces
What does an ectotherm do if it is too warm
- Move into the shade
- Expose less surface area to the sun
- Move underground
What do endotherms have that ectotherms do not
An internal source of heat due to metabolic reactions releasing heat
How do endotherms stay warm
- Insulate the internal sources of heat
How do hair and feathers provide insulation
In cold hair and feathers stand on end, creating an insulating layer of air
How can capillaries lower heat loss
Capillaries constrict so less blood flow is at skins surface so less heat is lost by radiation
How can respiration effect temperature
Respiration can be increased by the liver releasing more energy stores for conversion into heat
How can muscle contractions effect temperature
Spontaneous muscle contractions (shivering) can be used to generate hear
How can sweat cool body down
Heat is removed from the body when the water in the sweat is evaporated. Water has high latent heat of evaporation, so sweat holds a lot of heat before it is removed in evaporation
What do animals that cant sweat do
They pant which removes heat by evaporation of saliva
How can capillaries increase heat loss
Capillaries close to the skin undergo vasodilation, so more blood will be at surface to give off heat radiation
What is an advantage of being an endotherm
They can maintain their temperature despite changes in external temperatures. So they can be active in different temperatures in the day, so can inhabit colder parts of the earth
What is a disadvantage of being an endotherm
They spend a lot of energy keeping warm, so they need to find a lot more food. Also much more likely to overheat
