Gas Exchange in Fish Flashcards
Are fish waterproof?
Yes
What is the surface area to volume ratio for fish like?
Small surface area to volume ratio.
What is the gas exchange surface in fish?
Gills
Where do fish obtain oxygen from?
The water.
Why do fish need to adapt?
There is 30x less oxygen in the water than in air so they need to adapt to maintain the concentration gradient to enable diffusion to occur.
What are the 3 features of gas exchange surface?
Large surface are to volume ratio
Short diffusion distance
Maintained a concentration gradient
What can be used to calculate the rate of diffusion?
Fick’s Law
What is Fick’s Law?
Diffusion is proportional to - (Surface area x Difference in Concentration)/ Length of Diffusion Path
How many gills are on a fish and where are they?
4 gills on both sides of the head. 8 in total.
What are the gills made up of?
Stacks of gill filaments.
What is each gill filament covered in? What does this lead to?
Gill lamellae positioned at right angles to the filament. A large surface area.
Where does the diffusion of gases happen on fish?
On the lamellae.
When fish open their mouth, where does the water go?
Water rushes in and over the gills and then out through a hole in the sides of their head.
How is the large surface area to volume ratio created in fish?
Many gill filaments covered in many gill lamellae.
How is the short diffusion distance established in fish? (2)
The gill lamellae are very thin and the gill lamellae is where diffusion occurs.
Inside of every gill lamellae there is a capillary network that provides a short diffusion distance.
How is a concentration gradient maintained in fish?
Large number of capillaries which remove O2 and bring CO2 quickly.
What is meant by countercurrent flow?
This is when the water flows over the gills in the opposite direction to the flow of blood in capillaries.
What does the countercurrent flow ensure?
Equilibrium is not reached. There will never be the same concentration of oxygen in the blood as there is in the water.
What is ensured when equilibrium is not reached?
A diffusion gradient is maintained across the entire length of the gill lamellae.
What is the opposite of countercurrent flow?
Concurrent flow.
What occurs in concurrent flow?
Equilibrium is reached.
Describe the countercurrent flow.
Blood and water flow in opposite directions over lamellae so oxygen concentration is always higher in water. Thus, this maintains a conc gradient of O2 between water and blood for diffusion along the whole length of lamellae.
