Physiology
The electric eel has three abdominal pairs of organs that produce electricity: the main organ, the Hunter's organ, and the Sach's organ. These organs make up four-fifths of its body, and are what give the electric eel the ability to generate two types of electric organ discharges - low voltage and high voltage. These organs are made of electrocytes, lined up so a current of ions can flow through them and stacked so each one adds to a potential difference. When the eel locates its prey, the brain sends a signal through the nervous system to the electrocytes. This opens the ion channels, allowing sodium to flow through, reversing the polarity momentarily. By causing a sudden difference in electric potential, it generates an Electric current in a manner similar to a battery, in which stacked plates each produce an electrical potential difference. In the electric eel, some 5,000 to 6,000 stacked electroplaques are capable of producing a shock at up to 500 volts and 1 ampere of current (500 watts). Such a shock could be deadly for an adult human. Electrocution death is due to current flow; the level of current can be fatal in humans depending on the path the current takes through the human body. Heart fibrillation (which is reversible via a heart defibrillator) can take place from currents ranging from 70 to 700 mA and higher.
The Sach's organ is associated with electrolocation. Inside the organ are many muscle-like cells, called electrocytes. Each cell can only produce 0.15 V, though by working together, the organ can transmit a signal of about 10 V in amplitude at around 25 Hz in frequency. These signals are emitted by the main organ; the Hunter's organ can emit signals at rates of several hundred Hertz.
The electric eel is unique among the Gymnotiformes in having large electric organs capable of producing lethal discharges that allows them to stun prey. Larger voltages have been reported, but the typical output is sufficient to stun or deter virtually any other animal. Juveniles produce smaller voltages (about 100 V). They are capable of varying the intensity of the electrical discharge, using lower discharges for "hunting" and higher intensities for stunning prey, or defending themselves. When agitated, they are capable of producing these intermittent electrical shocks over a period of at least an hour without signs of tiring.
The electric eel also possesses high frequency-sensitive tuberous receptors distributed in patches over the body that seem useful for hunting other Gymnotiformes.
Electric eels have been widely used as a model in the study of bioelectrogenesis. The species is of some interest to researchers, who make use of its acetylcholinesterase and ATP.
Read more about this topic: Electric Eel
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