Pflueger Bags

Pflüger's sacs (Pflüger'sche Säcke) are extensions in the proximal part of the electrical organ of eels and rays. They were first described by the German physiologist Eduard Pflueger in 1877.

Pflueger's sacs are composed of many densely packed cells, or electrocytes. These cells produce electrical current through ion pumps in their membranes. The current is generated due to the difference in the concentrations of sodium and potassium ions on both sides of the membrane.

Charge is accumulated in these bags before being discharged into the electrical organ. The discharge is coordinated by the nervous system and is used by these fish for navigation, hunting and defense.

Pfluger's sacs play an important role in generating powerful electrical discharges in eels and rays. Their study has made a great contribution to the understanding of bioelectrical phenomena in living organisms.