Gas Exchange in Fish

Question 1

System fish have

Answer 1

Counter-current system

Question 2

Gas exchange process with structures

Answer 2

Bony gill -> blood vessel

Question 3

Advantage of gill filaments

Answer 3

1) Diffusion of O2 into blood takes place along whole length of gill providing large SA
2) Constantly maintaining water flow

Question 4

What does the counter current system ensure

Answer 4

concentration gradient is mantained along length of capillary

Question 5

What does the ventilation mechanism do

Answer 5

Constantly pushed water over surface of fills, constant supply of water rich in oxygen

Question 6

What does lowering their buckal cavity

Answer 6

Volume inside buccal cavity to increase
Decrease in pressure within buccal cavity

Question 7

Explain the advantage of the counter-current principle in gas
exchange across a fish gill

Answer 7

1) Water and blood flow in opposite directions
2) Maintains diffusion and concentration gradient of oxygen so, oxygen conc always higher in water than in fish
3) Diffusion occurs along whole length of lamellae and gill filament

Question 8

Explain two ways in which the structure of fish gills is adapted for efficient
gas exchange

Answer 8

1) Many lamellae / filaments so large surface area
2) Thin (surface) so short diffusion pathway

Question 9

Explain how the counter current mechanism in fish gills ensures the
maximum amount of the oxygen passes into the blood flowing through the
gill

Answer 9

1) Water and blood flow in opposite directions
2) Blood always passing water with a higher oxygen concentration
3) Diffusion gradient maintained throughout length of gill

Question 10

Explain how the CCP allows efficient oxygen uptake

Answer 10

Blood and water flow in opposite directions
Diffusion/concentration gradient maintained along gill filament

Question 11

Structure of gills in bony fish

Answer 11

Many Gills on each side f head
Each gill arch has two stacks of filaments
On surface of each filament there are rows of lamellae
Lamellae surface consists of single layer of flattened cells that cover vast network of capillaries

Question 12

What does the capillary system in the lamellae ensure

Answer 12

Blood flows in opposite direction to flow of water

Question 13

What structure keeps the counter current system working

Answer 13

Capillary system in lamellae
ensures blood flows in opposite directions to the flow of water (countercurrent)

Question 14

What are the structures of fish gills in bony fish

Answer 14

Gills on each side of head
Gill arch attached to two stacks of filaments
Rows of lamellar on surface of filament
Capillaries in lamellae