Discoveries in Bioelectricity

In the middle of the 18th century, a clue to discovering the true function of the "nerve fibers" that run throughout the body, which were discovered through dissection, was uncovered.

This discovery was made by an Italian physician, physicist and philosopher, Luigi Galvani in his "Discoveries in Bioelectricity" (Luigi Galvani：1737－1798).

In his experiments with the skinned leg of a frog, he fastened a copper hook into the frog's leg and hung it on a zinc galvanized iron railing. Then he noticed that the frogs' legs twitched when the wind blew and the frog's leg came in contact with the railing. (Fig.1)

He investigated the cause and clarified that it was due to the electricity which flowed between the copper hook and the zinc galvanized iron railing (caused by the difference in ionization tendencies between copper and zinc.) This discovery led shortly to the invention of an early electrical battery by Alessandro Volta and furthered electrical research.

Thus, Galvani realized that the "nerve fiber" was a cable to transmit electricity.Sensory information from the outside reaches the brain as an electrical signal, and the corresponding conditional reflex is transmitted from the brain to the muscles through the nerve fiber and causes movements. Galvani confirmed that the conditional reflex was lost when the fascicle of nerve fibers reaching its legs was cut; therefore he theorized that the signals going to and leaving the brain were using the same nerve fiber.

Challenge Quiz

1.

The person who discovered that the nerve fiber is a cable to transmit electricity was ( Galvani Volta Ampere  正解!).

2.

This discovery led to the realization that electricity flowed between two metals ( silver and zinc Iron and copper zinc and copper  正解!) due to differences in ionization tendencies.