exchange surface Flashcards
(7 cards)
factors that affect the need for an exchange system
size
surface area to volume ratio
level of activity
how does size affect exchange system
small organism - diffusion is sufficient enough
as the organism get bigger the diffusion pathway gets longer so diffusion is to slow to enable a sufficient supply to the innermost cell
SA:V ratio affect exchange system
as size increase the SA and V increase but the ratio decrease
level of activity affect exchange system
more active = more nutrients need as more energy (ATP) is need
feature of all exchange surface
-large SA
-thin, permeable layers
-short diffusion distance
-maintenances of steep concentration gradient
what is a another feature of mammalian lung have
surfactant - reduces the cohesion between water and stops the alveoli collapsing