---
title: "Conduction Speed: Myelination and the Refractory Period"
description: "Myelin makes the impulse jump between gaps, so a myelinated axon conducts far faster than a bare one of the same width. The refractory period caps the frequency and keeps the impulse travelling one wa"
canonical: https://lightmysky.com/learn/science/conduction-speed-myelination-and-the-refractory-period-mt_x3M0sv6oD6
source: https://lightmysky.com/learn/science/conduction-speed-myelination-and-the-refractory-period-mt_x3M0sv6oD6.md
retrieved: 2026-09-12
---

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# Conduction Speed: Myelination and the Refractory Period

Myelin makes the impulse jump between gaps, so a myelinated axon conducts far faster than a bare one of the same width. The refractory period caps the frequency and keeps the impulse travelling one way.

Subject: Science · Area: The Human Body · Ages 17 to 18
Page: https://lightmysky.com/learn/science/conduction-speed-myelination-and-the-refractory-period-mt_x3M0sv6oD6

## Ready when they can

- Explains why jumping between gaps is faster than conduction along a bare membrane.
- Names two other features of an axon that change conduction speed.
- Links the refractory period to both the direction and the maximum frequency of impulses.

## Lesson: Jump Gaps, Set the Pace

Myelin insulates the axon, leaving bare gaps called nodes of Ranvier. Voltage gated channels cluster at the nodes, so the spike regenerates there while charge spreads passively under the wrap. This jumping, called saltatory conduction, is far faster than opening channels along every patch.

Build sets speed three ways: wider axons meet less resistance, myelin adds the jumping trick, and warmth speeds channels until proteins cook. Losing myelin slows and weakens conduction, as multiple sclerosis shows.

**Example.** After each spike comes the refractory period, when sodium channels inactivate and no stimulus can fire another spike there. The patch behind is exhausted while the patch ahead is fresh, so travel stays one way.

**Tip.** The same breather caps the rate: about 2 milliseconds of recovery allows at most about 500 spikes per second. Frequency can code strength only inside that ceiling.

**Recap.** Myelin makes impulses jump between nodes, width and warmth tune the pace, and the refractory period keeps traffic one way and capped.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [The Resting Potential and the Action Potential](https://lightmysky.com/learn/science/the-resting-potential-and-the-action-potential-mt_0sh4w30ocz)

## Opens up

- [Synaptic Transmission, Summation and Inhibition](https://lightmysky.com/learn/science/synaptic-transmission-summation-and-inhibition-mt_0uM8xRV92B)
- [Cable Properties and Dendritic Integration](https://lightmysky.com/learn/science/cable-properties-and-dendritic-integration-mt_bbPl-eJUFF)
- [Hearing and Balance: Frequency, Place and Head Motion](https://lightmysky.com/learn/science/hearing-and-balance-frequency-place-and-head-motion-mt_qzPAt9JMOZ)