exhange and transport systems (plants/insects/fish) Flashcards
what is the purpose of an exoskeleton?
fibrous for protection, lipids prevent water loss
what is the tracheal system in insects made from?
trachea, tracheoles, spiracles
what are the adaptations of an insect to limit water loss?
small surface area:volume where water evaporates from
waterproof exoskeleton
spiracles can open/close to prevent water loss
what happens in the spiracles?
gases can enter and leave
what do the trachea have?
rings to strengthen them and keep them open
what do the tracheoles do?
extend to tissues to deliver oxygen
how does gas exchange occur in insects?
mass transport uses rhythmic and abdominal movements
concentration gradient from tracheoles to atmosphere allows diffusion to occur
how does anaerobic respiration occur in insects?
lactase lowers the water potential of cells
water moves in by osmosis from the tracheoles
which decreases the volume of the tracheoles
air is drawn in
how can insects control water loss?
close spiracles using muscles
waterproof, waxy cuticle over their body
tiny hairs around spiracles to reduce evaporation
what is the role of the epidermis?
limits water loss and controls gas exchange
what is the role of the palisade mesophyll?
contains chloroplasts for photosynthesis
what is the purpose of the spongy mesophyll?
for gas diffusion to occur
what is the role of guard cells?
controls what enters and leaves the plant
what is the role of the stomata?
close at night to prevent water loss
when are guard cells kept open?
during the day
what happens when water enters guard cells?
makes them turgid, which opens the stomatal pore
what happens to guard cells if a plant starts to get dehydrated?
guard cells lose water and become flacid, which closes the pore
what is a xerophyte?
plant which needs very little water
what are examples of xerophytic adaptations?
stomata sunken in pits trap moist air, which reduces the concentration gradeint of water between the leaf and air= less evaporation
hairs on the epidermis to trap moist air around the stomata
curled leaves with the stomata inside- protection from wind which increases evaporation
reduced number of stomata so fewer places for water to escape
waxy, waterproof cuticles on leaves/ stems to reduce evaporation
how does water pass through a fish?
fish opens its mouth volume of the buccal cavity increases pressure increases water flows in fish closes its mouth squeezes water out of the buccal cavity over the gills and out of the operculum
what is the structure of the gill in a fish?
2 piles of soft thin plates- lamellae
attached to bony gill arch
lamellae on top of eachother
kept apart by water
what is the role of the afferent artery?
brings deoxygenated blood from the heart
what is the role of the efferent artery?
brings oxygenated blood from the gills to the tissues
how do fish gills have a large surface area?
gill made of thin plates= gill filaments- large SA for gas exchange
gill filaments covered in lamellae- increase surface area further
lamallae have blood capillaries
how does the counter current flow ensure efficent gas exchange?
blood flows through the lamellae and water flows over the lamellae in opposite directions
maintains a large concentration gradient between the water and the blood
concentration of oxygen in water always higher than the blood- so as much oxygen as possible diffuses from the water into the blood
