BRAINCAKEInvestigating Nerve Impulses
Much of what we know about nerve impulses came from experiments by Hodgkin and Huxley in the 1940s and 1950s on the giant axon of the squid. Its large diameter (up to about 1 mm) made it possible to insert a fine electrode inside it.
The potential difference across the membrane is measured using two microelectrodes. One, a fine glass tube filled with a conducting salt solution, is inserted inside the axon. The other is a reference electrode in the fluid outside the axon. The electrodes are connected through an amplifier to an oscilloscope (or a computer data logger), which displays the potential difference in millivolts against time in milliseconds.
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More in Mammalian Nervous System
- Structure and Function of Neurones
- Nerve Impulses
- Myelinated Neurones
- Speed of Nerve Impulses
- Resting Potential
- Action Potential
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All 38 lessons in Mammalian Nervous System · All Edexcel A-level Biology topics