From gill arch to lamella
Fish obtain oxygen from water using gills, which are found on either side of the head. Each gill is organised around a supporting gill arch.
- Each gill arch supports rows of long gill filaments.
- Each filament carries many smaller projections called lamellae.
- The surface of a lamella is formed from a single layer of flattened cells.
- A network of capillaries lies immediately beneath this thin exchange surface.
This repeated branching from arches to filaments and then lamellae produces a very large area over which oxygen can enter the blood.