gas exchange in insects and fish Flashcards
explain how air reaches the insects cells for gas exchange
- oxygen enters via spiracles on their exoskeleton surface
- it travels through air filled tubes called trachea
- trachea then branches into tracheoles which takes the oxygen to the cells
how are the tracheoles well adapted for gas exchange
- thin walls
- highly branched
how are gills well adapted to gas exchange
- they have gill filaments which increases surface area
- the gill filaments have lamella which further increases the surface area
- lamella are also thin and have a good blood supply
what is concurrent flow
this is when the blood and water are flowing across the lamella in the same direction
describe concurrent flow
- the concentration gradient starts off large
- as the blood and water move across the lamella, the oxygen from water will diffuse into the blood
- eventually the concentration gradient will reach equalibrium until no more oxygen can diffuse into the blood
as a result of this, only littl oxygen can diffuse into the blood due to the concentration only being present across part of the lamella
what is countercurrent flow
this is when the water and blood are flowing in opposite directions, it maintains a high concentration gradient across the whole lamella and so the blood can become highly saturated with oxygen
what allows the lamella to be well supported
a good flow of water to the gills
describe the process of ventilation in fish
- mouth opens and operculum shuts
- this causes a decrease in pressure forcing water to be drawn in
- the mouth then shuts and so the operculum can open
- this increases the pressure forcing water out across the gills
desribe the ventilation of an insect
they have muscles which contract and compress the trachea
this forces air in and out - depending on the pressure
explain how ventilation differs when respiration levels are high
ventilation will occur more frequently in order to remove carbon dioxide
