Here's a breakdown:
* Gills: These are feathery organs that are highly vascularized (contain many blood vessels).
* Gill Filaments: The gills are composed of thin, folded structures called gill filaments. These filaments increase the surface area for gas exchange.
* Lamellae: Each gill filament is further subdivided into even smaller, folded structures called lamellae. These lamellae are where the actual gas exchange takes place.
The gills allow the fish to extract oxygen from the water and release carbon dioxide back into the water. This process is made possible by the thin and permeable membranes of the lamellae, allowing for diffusion of gases across the concentration gradient.