Homeostasis Flashcards Preview

Biology: topic 16 > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (6):

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


What are endotherms?

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


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


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


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


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

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