Gas Exchange in Fish

Question 1

What is the structure of a fish gill?

Answer 1

=Gill Filaments
-Planes that extend off of blood-supplied gill bar
-Increase SA for gas exchange

=Gill Lamellae
-At 90 degree angles to the gill filaments
-Increase SA for gas exchange

Question 2

How is water passed along fish gills?

Answer 2

Water flows over the gill filaments in the opposite direction of blood flow.

Question 3

What is the difference to parallel flow and counter current flow?

Answer 3

PARALLEL FLOW
Water and blood flow in the same direction.

COUNTER-CURRENT FLOW
Water and blood flow in opposite directions to each other.

Question 4

How does counter-current flow maintain a constant rate of increased gas exchange?

Answer 4

If blood and water are flowing in opposite directions then a constant concentration gradient is maintained, increasing the rate of gas exchange.