Gas Exchange Flashcards
What is the tracheal system?
Network of small tubes called tracheoles to carry oxygen around the body.
What are the openings along an insects thorax and abdomen?
Spiracles
What are spiracles function?
Gases diffuse through into and out the tracheoles.
Prevents water loss.
Is the tracheal system efficient?
Yes
It is the most efficient gas exchange system.
What are gills?
Filaments of thin tissue that are highly branched and folded.
Why is the structure of gills helpful?
Creates a large surface area for diffusion.
Also has lamellae attached which further increases the surface area.
What is the counter current system?
Blood flows through lamallae in opposite direction as water flows through the gills.
Maintains a steep concentration gradient for constant diffusion.
Do fish have a small or large surface area to volume ratio?
Small surface area to volume ratio so requires a specialised gas exchange system.
What features maximise gas exchange in fish?
Large surface area to volume ratio
Short diffusion distance
Maintained conc gradient
What is Fick’s law?
Diffusion = (s.a x diff in conc) / length of diffusion path
What is fish anatomy going from gills to lamellae?
Four layers of gills which are made up of stacks of gill filaments. These gill filaments have lots of lamellae on them.
Benefit of lamellae?
Creates a large surface area for faster diffusion
What happens when a fish opens its mouth?
Water rushes in and over the gills then out through a hole in the side of the head
How does fish keep a large surface area to volume ratio?
Many gill filaments with many lamellae
How does fish keep a short diffusion distance?
lamellae are very thin and have an extremely large capillary network running into each one
How does fish keep a constant concentration gradient?
Countercurrent flow mechanism
What is the countercurrent flow mechanism?
Where water runs over the gills in the opposite direction of where the blood runs through the capillaries.
This ensures equilibrium never occurs as constant diffusion occurs.
What’s the benefit of countercurrent flow mechanism?
Ensures a diffusion gradient is maintained across the entire length of gill lamellae.
What is concurrent flow mechanism?
Where the blood and water/air flow in the same direction so at some point, equilibrium is reached and a concentration gradient is lost.
Why do insects have an exoskeleton?
Hard fibrous material for protection
Why do insects have a lipid layer?
To prevent water loss
Why do insects have a tracheal system and not lungs?
High surface area to volume ratio so do not need a specialised gas exchange system
What adaptations do insects have to limit water loss?
Small surface area to volume ratio that water can evaporate from
Insects have a waterproof exoskeleton
Spiracles can relax and contract to control water movement.
What are spiracles?
Round, valve like openings across the abdomen which can open and closer to allow for movement of oxygen, carbon dioxide and water.
The trachea are attached to these openings.
