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Biology: topic 16 > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (6):
1

What is homeostasis?

-the maintenance of an internal environment in organisms
-ensures cells environment allows them to function normally despite external changes
-blood and tissue fluid volume and pH is maintained to prevents enzymes and other proteins becoming denatured
-changes to water potential of blood and tissue fluid, could cause cells to shrink or burst
-glucose concentration must be maintained so that cells can respire

2

What are endotherms?

-animals such as birds and mammals derive most of their heat from the metabolic activities that tale place inside their bodies

3

What are ectotherms?

-many ectotherms gain heat from the environment, they control their body temperature by adapting their behaviour to changes in the external temperature

4

How do animals conserve and gain heat in response to a cold environment?

-small surface area to volume ratio so less heat is lost
-have smaller ears
- thicker fur or layers of fat

5

Which mechanisms allow mammals to make more rapid body temperature changes?

-vasoconstriction makes blood vessels near the skin surface smaller so less heat is lost
-shivering increases metabolic activity to produce more energy
-raising of hair means still air is trapped near the skin surface
-decrease in sweating means less energy is wasted
-behavioural mechanisms take shelter from the cold or get into the sun

6

How do animals lose heat in response to a warm environment?

-large surface area to volume ratio - lighter coloured fur to reflect heat