3.1 Flashcards
what is gas exchange?
the diffusion of O2/CO2 across an exchange surface
how are exchange surfaces adapted?
a large surface area, thin, good blood supply, ventilated, moist
what is the quantitative connection between surface area and volume?
as side length doubles, sa:vol halves
what is the gas exchange surface for fish?
gills
why do fish need a specialised gas exchange surface?
small sa:vol, high metabolic rate, high demand for O2, can’t be met by diffusion across body surface
how do gills have a large surface area?
lots of gill filaments and each filament has lots of gill lamellae
how do gills have short diffusion distance?
gill filaments/ lamellae are squamous epithelial
how do gills have a good blood supply?
lots of capillaries
how do gills have a method to maintains concentration gradients?
counter current flow
what is counter current flow?
water moving across the gills and blood in the capillaries of the gills are moving in opposite directions
what does counter current flow mean?
concentration gradient for O2 is maintained across the whole gill lamellae
what happens in the fish when they take in water?
1- the mouth opens
2- the operculum closes
3- the floor of the mouth is lowered
4- the volume inside the mouth cavity increases and pressure decreases
5- water flows in as the external pressure is higher than the pressure inside
what happens when a fish to force water out over the gills?
1- the mouth closes
2- the operculum opens
3- the floor of mouth is raised
4- the volume inside mouth decreases and the pressure increases
5- water flows out over the gills because the pressure in the mouth is higher than in the opercular cavity and outside
what adaptations do amoebas have?
their gas exchange surface is plasma membrane, large sa:vol so has a short diffusion pathway
what adaptations do flatworms have?
flat so increase in sa:vol, gas exchange over body surface due to short diffusion pathways
what adaptations are in earthworms?
elongated so has an increase in sa:vol, has exchange over body surface, body surface is moist (secrete mucus)
what adaptations do amphibians have?
live in moist habitats, water for fertilisation, tadpoles live in water and have gills, transition to land living in metamorphosis, inactive adults use moist skin as respiratory surface, active (mating) adults use lungs
what adaptations do reptiles have?
pairs of ribs project from vertebrae, provide support + protection and involved in ventilation, have in-growth of tissues to increase surface area
what adaptations do birds have?
system of air sacs, when breathing in any remaining air from previous ventilation is sucked into sacs, ribs cause ventilation, during flight flight muscles ventilate, very efficient with basically no residual gas
what is the structure of the trachea?
c shaped cartilage, ciliated epithelium with glands