Other Free Encyclopedias » Online Encyclopedia » Encyclopedia - Featured Articles » Contributed Topics from F-J

Hodgkin, Sir Alan Lloyd

nerve axon potential membrane

(1914–98) British neurophysiologist: major contributor to understanding of nerve impulses.

As a student of biology and chemistry in Cambridge, Hodgkin became interested in the basis of nervous conduction, and he found by accident that it was easy to obtain single nerve fibres from a shore crab and that these could be used in experiments despite their small size (diameter about 35 µm). In the USA in 1938 he was impressed by the possibility of using larger nerve fibres from the squid. Some squids (the genus Loligo ) are half a metre long and highly active, and have giant nerve fibres up to 1 mm in diameter.

It had long been known that a nerve impulse is electrical and that a major nerve fibre (axon) acts as a cable, but detailed knowledge was much advanced by the work of Hodgkin and his colleagues, especially A F Huxley (1917–97). Their study of the squid axon began in 1939, was interrupted by their war service, and continued after 1945. They were able to insert a fine microelectrode into an axon and place a second electrode on the outer surface of its surrounding membrane. Even in a resting state there is a potential difference between the electrodes: the negative ‘inside’ has a resting potential compared with the positive exterior surface. When an impulse passes, this is reversed by the action potential for about a millisecond; the nerve impulse is a wave of depolarization passing along the axon. Hodgkin developed a detailed theory of the origin of this membrane potential, relating it to the presence of sodium and potassium ions and their distribution across the membrane. This knowledge of the biophysics of nervous conduction is basic to further understanding of the nervous system, and Hodgkin and Huxley shared a Nobel Prize in 1963 with J C Eccles (1903–97), who also worked on nerve transmission. Hodgkin became president of the Royal Society in 1970, and Master of Trinity College, Cambridge, 1978–84.

Hoff, Jacobus Henrikus van 't [next] [back] Hodgkin, Dorothy,

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or