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Internal Anatomy
Gas Gland
Glandula gaseosa
Specialised tissue on the swim bladder wall that secretes oxygen and other gases against extreme pressure gradients - the biological engineering that lets fish adjust depth.
Region: Trunk Unique to: bony
📖 Overview
Bony fish without a duct connecting swim bladder to gut (physoclistous species) rely on the gas gland to inflate the bladder. Blood delivered to the gas gland becomes hyperacidified, forcing dissolved oxygen out of hemoglobin (the Root effect). A parallel rete mirabile amplifies this into oxygen concentrations high enough to fill the bladder against 200+ atmospheres of pressure.
🧬 Structure
Thickened area of the swim bladder wall lined with specialised acid-secreting epithelial cells. Backed by a rete mirabile - a dense countercurrent network of capillaries.
✨ Fun Fact
The gas gland of deep-sea fish can concentrate oxygen to purity levels higher than industrial oxygen tanks - a metabolic marvel accomplished with only cells and blood.
🔗 Related Internal Structures