Squid giant axon

Between the tentacles of a squid is a siphon through which water can be rapidly expelled by the fast contractions of the body wall muscles of the animal. This contraction is initiated by action potentials in the giant axon. Action potentials travel faster in a larger axon than a smaller one, and squid have evolved the giant axon to improve the speed of their escape response. This has obvious^{[citation needed]} adaptive advantage when escaping from predators.

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In their Nobel Prize-winning work uncovering ionic mechanism of action potentials, Alan Hodgkin and Andrew Huxley performed experiments on the squid giant axon. The large diameter of the axon provided a great experimental advantage for Hodgkin and Huxley as it allowed them to insert voltage clamp electrodes inside the lumen of the axon.

See also

• Lateral giant neuron