Fish ventilation Flashcards
what is stage one of breathing in?
operculum valve is shut
what is stage two of breathing in?
mouth opens
what is stage three of breathing in?
floor of buccal cavity is lowered
what is stage four of breathing in?
volume increases
what is stage five of breathing in?
pressure falls
what is stage six of breathing in?
water moves into the mouth (high to low pressure)
what is stage one of breathing out?
operculum valve opens
what is stage two of breathing out?
mouth closes
what is stage three of breathing out?
floor of buccal cavity moves up
what is stage four of breathing out?
volume decreases
what is stage five of breathing out?
pressure increases
what is stage six of breathing out?
water flows out over gills (high to low pressure)
What is counter current flow?
2 liquids flow across each other in opposite directions, separated by a membrane.
Maintains diffusion gradient.
What two liquids in fish use counter current flow?
Blood and water filtered through the gills
Why does counter current flow allow more oxygen to enter the blood (7 marks)
Blood and water flow in opposite directions.
High oxygenated water meets high oxygenated blood.
Low oxygenated water meets low oxygenated blood.
This maintains concentration gradient.
Have diffusion along entire length of blood flow.
In parallel water and blood flow same direction.
This means oxygen levels equalise and limit diffusion
