Homeostasis

Question 1

What is homeostasis?

Answer 1

• 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

Question 2

What are endotherms?

Answer 2

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

Question 3

What are ectotherms?

Answer 3

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

Question 4

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

Answer 4

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

Question 5

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

Answer 5

• 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

Question 6

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

Answer 6

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