Exchange Surfaces & Breathing Flashcards
what substances needed to pass across exchange surfaces
water, oxygen, minerals, proteins, fats, glucose
waste products
carbon dioxide, oxygen, ammonia, urea
features of perfect specialised exchange surfaces
large SA
thin barrier
steep concentration gradient
small animals
large SA/V ratio
diffusion across external surface able to provide all respiratory needs
large animals
small SA/V ratio
gas exchange over body surface can’t satisfy needs so need special surfaces
gaseous exchange
the movement of gases between an organism and its environment
diffusion rate at gas exchange depends on
SA of surface
difference in concentration
length of diffusion pathway
main site of gas exchange
alveoli (little across walls of bronchioles)
partial pressure of oxygen
a measure of how much of the whole atmospheric pressure is due to the oxygen present in it
partial pressure measured in
kilopascals
why would airways collapse if cartilage didn’t support it
during inspiration pressure inside airway is lower than normal so if no support likely to collapse
why are blood vessels important in lung tissues
the more blood vessels with larger SA the faster the rate of diffusion of gases
why are there many filaments and lamellae in fish
filaments very thin so short gas exchange pathway
lots to increase surface area for faster rate of gas exchange
why will sharks drown if they stop moving
there will be no countercurrent flow as there won’t be a flow of water over the lamellae
when inspiring the trace on a sprirometer graph will
dip down
