Chapter 18, Problem 53P

To determine

The speed of the electric pulse along the axon.

Answer to Problem 53P

  $34.545m/s$

Explanation of Solution

Given info:

Change in time, $\Delta t=0.0063s-0.0052s$

Change in distance, $\Delta x=0.0720m-0.0340m$ .

Formula used:

Formula used to calculate an average speed:

  $v=\frac{\Delta x}{\Delta t}$

Where, $\Delta t$ is change in time and $\Delta x$ is a change in distance.

Calculation:

Substitute all the given values in expression, $v=\frac{\Delta x}{\Delta t}$

  $\begin{array}{c}v=\frac{0.0720m-0.0340m}{0.0063s-0.0052s}\\ =\frac{0.038m}{0.0011s}\\ =34.545m/s\end{array}$

Also, two measurements are needed because transitory effects between the moment of electrical stimulation and propagation of the action potential mean that no one can assume that the position of the action potential is at $x=0$ when $t=0$ .

Conclusion: The speed of the electric pulse along the axon is $34.545m/s$ .