Ventilation in fish

Question 1

The ventilation mechanism in fish constantly pushes water over the …………………… and ensures they are constantly supplied with water rich in oxygen (…………………….

Answer 1

surface of the gills

maintaining the concentration gradient

Question 2

When the fish open their mouth they lower the floor of the buccal cavity. This causes the volume inside the buccal cavity to …………, which causes a …………… within the cavity

The pressure is higher …………………….. and so water flows into the ………………..

Answer 2

increase

decrease in pressure

outside the mouth of the fish

buccal cavity

Question 3

The fish then raises the floor of the buccal cavity to close its mouth, ………………..the pressure within the buccal cavity

Answer 3

increasing

Question 4

Water flows from the ………………… (high pressure) into the …………… (low pressure)

Answer 4

buccal cavity

Question 5

As water enters …………begins to build up in the gill cavity and causes the operculum (a flap of tissue covering the gills) to be forced ……………and water to ……………..the fish

Answer 5

pressure

operculum

open

exit

Question 6

The operculum is pulled shut when the floor of the …………………. at the start of the next cycle

Answer 6

buccal cavity is lowered