7.1 Specialised Exchange Surfaces Flashcards
What do specialised exchange surfaces do for organisms with high metabolic activity & low surface area:volume?
Increase rate & efficiency of diffusion to meet high demands.
What factors determine the need for specialised exchange surfaces?
metabolic rate, surface area:volume
What factors mean an organism may require a specialised exchange surface?
high metabolic rate, low surface area:volume
What factors mean an organism may not require a specialised exchange surface?
low metabolic rate, high surface area:volume
How does low metabolic rate determine the need for a specialised exchange surface?
LOW DEMAND for O2 + CO2 removal,
organism CAN RELY on DIFFUSION to meet demand
High rate of metabolic activity =
HIGH DEMAND for O2 + CO2 removal,
organism CANNOT RELY on DIFFUSION to meet demand
High SA:V =
SHORT diffusion distance,
can rely on diffusion to meet demand,
no specialised exchange surface required
Low SA:V =
LARGE diffusion distance,
cannot rely on diffusion to meet demand,
specialised exchange surface required
Surface area to volume ratio shows how large the surface area is in _____ to the volume.
proportion
Characteristics of efficient exchange surfaces:
high SA,
short diffusion distance,
good blood supply,
ventilation
What is the effect of a specialised exchange surface having a HIGH SURFACE AREA?
faster RATE of diffusion
What is the effect of a specialised exchange surface having a GOOD BLOOD SUPPLY/VENTILATION?
maintains STEEP CONCENTRATION GRADIENT by removing diffused substances
What factors affect the rate of diffusion?
temperature, surface area, diffusion distance, concentration gradient
Surface area of a sphere =
4πr^2
Volume of a sphere =
(4/3)πr^3
