Diatoms and Dinoflagellates / Fifth Dimension

Gills usually consist of a thin filament tissue, lamellae
Tufted processes that have highly folded surfaces to increase surface area
The delicate nature of gills is possible because the surrounding water provides support
The blood or other body fluid must be in it to make contact with the respiratory surface for ease of diffusion
The high surface area is crucial to the gas exchange of aquatic organisms
Water only contains a small fraction of oxygen that air does
Water is 777 times more dense than air and is 100 times more viscous
Oxygen has a diffusion rate in air 10,000 times greater than in water
The density of water prevents the gills from collapsing and lying on top of each other
Which is what happens when a fish is taken out of water
Usually water is moved across gills in one direction like [?]
When a fish breathes, it draws a mouthful of water at regular intervals
Then it draws the sides of its throat together, forcing the water through the gill openings
So that it passes over the gills to the outside
The gills of vertebrates typically develop in the walls of the pharynx, Along a series of gill slits opening to the exterior
Most species employ a counter-current exchange system to enhance the diffusion of substances in and out of the gill
With blood and water flowing in opposite directions to each other
The gills are composed of comb-like filaments, the gill lamellae, which help increase their surface area for oxygen exchange