experiment with the nerve indicated that speed of nervous impulse was?

Experiment:

Researcher: Hermann von Helmholtz (1850)

Method:

1. A muscle (gastrocnemius) was stimulated directly and the time taken for the muscle to contract was measured.

2. A nerve (sciatic nerve) was stimulated at two different points, with a known distance between them, and the time taken for the muscle to contract was measured.

Results:

The time taken for the muscle to contract was shorter when the nerve was stimulated closer to the muscle than when it was stimulated further away. This suggested that the speed of the nervous impulse was finite and not instantaneous.

Calculations:

The speed of the nervous impulse was calculated by dividing the distance between the two points of stimulation by the difference in the time taken for the muscle to contract.

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Speed of nervous impulse = Distance between points of stimulation / Difference in time

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In Helmholtz's experiment, the distance between the two points of stimulation was 3 m and the difference in time was 0.002 s.

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Speed of nervous impulse = 3 m / 0.002 s = 1500 m/s

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Therefore, the speed of the nervous impulse in the sciatic nerve of a frog was found to be approximately 1500 m/s.

Conclusion:

Helmholtz's experiment showed that the speed of the nervous impulse is finite and not instantaneous. This finding was important for understanding how the nervous system communicates and processes information.