What is the myelin sheath?

  • Google+ icon
  • LinkedIn icon
  • 842 views

The myelin sheath is a layer of insulating, fatty material that encases some neurones. The sheath is composed of Schwann cells that have gaps called nodes of Ranvier between them. Potassium and sodium ions can only diffuse in and out of the neurone at these gaps. This allows saltatory or 'jumping' conduction where the local currents are elongated as the sodium ions have to diffuse further along the neurone before the action potential can occur. The action potential appears to 'jump' from one node of Ranvier to another.

Alice H. GCSE Biology tutor, GCSE Chemistry tutor, GCSE Maths tutor, ...

About the author

is an online A Level Biology tutor with MyTutor studying at Bristol University

Still stuck? Get one-to-one help from a personally interviewed subject specialist.

95% of our customers rate us

Browse tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok