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Circulatory Anatomy
Fish Spleen
Lien
The primary blood-filtering and immune organ - dark red, sitting near the intestine, and central to red blood cell recycling.
Region: Trunk Universal in fish Unique to: all
📖 Overview
The fish spleen filters aged red blood cells, stores erythrocyte reserves, and participates in immune surveillance. In many species it doubles in size during activity or stress, releasing stored red cells to boost oxygen-carrying capacity.
🧬 Structure
Compact, dark red-brown organ near the stomach or intestine. Rich in phagocytic cells, red pulp (blood filtration), and lymphoid tissue.
⚙️ Function
Erythrocyte storage and release, blood filtration, immune cell production, iron recycling from senescent red cells.
✨ Fun Fact
A tuna spleen can nearly double in volume during a burst chase and shrink back within hours - a natural blood doping system.
🔗 Related Circulatory Structures