Gas Exchange Flashcards
(47 cards)
Why do larger animals need a specialised oxygen uptake system?
Large organisms have smaller surface area:volume ratio.
What does a specialised system in larger animals overcome?
Long diffusion pathway.
What does a specialised system in larger animals allow?
Faster rate of diffusion.
How does oxygen enter an insect?
Diffuses in through the spiracles.
What happens to the spiracle after oxygen enters?
Spiracle closes.
Where does oxygen go after the trachea in insects?
Into the tracheoles.
Where is oxygen delivered in insects?
Directly to the respiring tissues.
Why do tracheoles have thin walls?
For short diffusion distance to cells.
Why are tracheoles highly branched?
To give large surface area for gas exchange.
What do tracheae provide for gas movement?
Tubes full of air for fast diffusion.
What happens to tracheole fluid during exercise?
Moves out into tissues.
Why does fluid move out of tracheoles during exercise?
So diffusion is faster through air.
What does body movement in insects do for gas exchange?
Moves air to maintain diffusion gradient.
What structures make up the insect gas exchange system?
Spiracles, tracheae, tracheoles.
What allows oxygen to diffuse into an insect?
Spiracles.
What makes diffusion efficient in the insect gas system?
Highly branched tracheoles = large surface area.
Why are tracheole walls thin?
For short diffusion distance to cells.
Why can oxygen easily pass through tracheoles?
Tracheoles are permeable to oxygen/air.
What structure in insects reduces water loss?
Cuticle/chitin/exoskeleton (impermeable).
How do spiracles help reduce water loss?
Can close / have valves.
What do hairs around spiracles do?
Reduce water loss.
In the counter-current principle, how do water and blood flow?
In opposite directions.
What does counter-current flow maintain?
Oxygen diffusion/concentration gradient.
Where does diffusion happen in the gill?
Along the length of lamellae/filament/gill/capillary.
