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In this video, we look at gas exchange in bony fish. First we explore the structure of the gills, including the gill arches, gill filaments and gill lamellae. We then look at how the structure of the gill lamellae are adapted for efficient diffusion of gases. We then explore how the gill lamellae use a counter-current exchange system to increase the rate of diffusion. Finally, we look at how bony fish maintain a constant water flow over their gills.

This video is aimed at the UK A Level Biology specifications. Students studying International A Level Biology will need to check their specification.

Image Credits:

Tuna
https://commons.wikimedia.org/wiki/Fi...
Stephane-bdc, CC BY-SA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Salmon
https://commons.wikimedia.org/wiki/Fi...
Hans-Petter Fjeld, CC BY-SA 2.5 https://creativecommons.org/licenses/..., via Wikimedia Commons

Cod
https://commons.wikimedia.org/wiki/Fi...
Hans-Petter Fjeld, CC BY-SA 2.5 https://creativecommons.org/licenses/..., via Wikimedia Commons

Trout
https://commons.wikimedia.org/wiki/Fi...
Public domain

Carp with missing operculum
https://commons.wikimedia.org/wiki/Fi...
Guitardude012, CC BY 3.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Tuna gills
https://commons.wikimedia.org/wiki/Fi...
Chris 73 https://creativecommons.org/licenses/...

Gill Arches
https://commons.wikimedia.org/wiki/Fi...
User:Uwe Gille, CC BY-SA 3.0 http://creativecommons.org/licenses/b..., via Wikimedia Commons