The gill arches have gill stamens on the inside and gill petals on the outside. The gill filaments, pierced by a huge number of tiny blood vessels, absorb oxygen from the water as it passes through the gills. The gill lobes attach directly to the gill arches, hanging freely in the gill cavity.
Gill filaments are plates located in a double row on the back side of the gill arch, abundantly pierced with a dense network of blood capillaries where blood is enriched with oxygen dissolved in water. The gill filaments are formed from the ectoderm.
The gill lobes on one side of the septum form the gill pouch. Consequently, the gill consists of two gill lobes on the same gill arch, and the set of two gill lobes facing the same gill slit forms the gill sac.
Tags: gill petals