... like I'm 5 years old
Electric eels generate electricity in a way similar to how you would generate static electricity by rubbing a balloon against your hair. They have specialized cells called "electrocytes" that act like tiny batteries. When an eel decides it needs to produce a shock, its brain sends a signal to these cells, which then discharge their stored energy all at once. This generates a current of electricity that flows through the water and into anything that happens to be nearby. This is how electric eels stun their prey and defend themselves.
Imagine you're lining up a bunch of small batteries from end to end. Each battery on its own isn't very powerful, but when you add them all up, you get a much stronger current. That's a bit like what's happening inside an electric eel.
... like I'm in College
Diving deeper into the biology of an electric eel, these creatures have three pairs of abdominal organs that produce electricity: the main organ, the Hunter's organ, and the Sach's organ. These organs make up about four-fifths of its body and are packed with roughly 6,000 stacked electrocytes. Each electrocyte operates like a battery, having a positive and negative side. When the eel is idle, the ions, or charged particles, are distributed evenly across the electrocyte. However, when the eel is stimulated and a signal is sent from the brain, it opens ion channels on the cell membrane, allowing sodium ions to flow through and flip the electrocyte's charge. Releasing this charge from thousands of cells at once generates a substantial electric shock.
If we were to explain this process using Lego blocks, imagine building a Lego wall. Each Lego block represents an electrocyte. The wall itself is the electric organ. By themselves, each Lego block (or electrocyte) is harmless. But when you stack them together, you have a formidable Lego wall (or electric organ). Now, imagine a lever attached to your Lego wall that can tip all the blocks over at once. This lever represents the eel's brain, which sends the signal to discharge. When you push the lever (or when the eel is threatened), all the blocks (or electrocytes) tip over at once, releasing a surge of energy that represents the electric eel's shock. This simple model gives you an idea of how the eel's specialized cells work together to produce a powerful defensive weapon.
... like I'm an expert
From an electrophysiological perspective, the electrocytes in the electric eel operate via an action potential. Under resting conditions, the electrocyte maintains a voltage across its membrane, with the interior being negatively charged relative to the exterior. The sudden opening of sodium channels upon stimulation by the eel's nervous system allows for a rapid influx of sodium ions, reversing the voltage and creating a positive charge inside. This is the action potential. Given the arrangement of electrocytes in series and parallel, the sum of these action potentials can generate voltages up to 600 volts, a significant electric discharge.