Hey there! Sign in to join this conversationNew here? Join for free to post

Myelin sheath help

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
REMINDER: Do not post your personal statement on TSR, otherwise you may have to rewrite it from scratch. Click here for more info. 12-10-2016
    • Thread Starter

    Hi, guys!I'm in my AS year and I'm doing an assignment on the myelin sheath. Could someone help me out in terms of the formation and function of the sheath, like how it's made?I know that in the PNS the Schwann cells coat the axon and that forms the sheath but for the CNS, all I know is that oligodendrocytes make the sheath.If someone could hint or push me in the right direction for these questions, it would be awesome!What's the function of the myelin sheath?How is the sheath formed and the chemical composition?
    What si the effect of demyelination on the neurone?

    I know that the function of the myelin sheath is to increase the speed at which the signal travels along the axon - from AS psych. From this I'd take a guess that the effect of demyelinated would be that the signal travels slower.

    In terms of how it's formed - just google it:
    for example: "The myelin sheath is formed as individual cells extend their plasma membranes around the axons of neurons in a spiral fashion. In the central nervous system, these are called oligodendroglial cells, while in the peripheral nervous system, they are called Schwann cells.
    https://www.reference.com/science/myelin-sheath-formed-2474970320af894 "

    demyelination: https://www.google.co.uk/webhp?sourc...=demyelination

    I assume what you are being asked is to understand nerve impulses. An idea of your depth of knowledge, and desired detail, would be helpful. As you're in AS I shall assume that you are being guided towards understanding that myelin sheathes allow something called the Nodes of Ranvier. These nodes, allow something called saltatory conduction (the phrasing being derived from the latin for jump) as that is what happens. Instead of along a nerve continuously the action potential is propagated along at these nodes, allowing it to jump, thus being far quicker than normal conduction. This is useful for numerous reasons, for instance in reflex arcs it speeds up an already quick process.

    As such in answering your final question, a removal of this removes the benefits of it. In other words it slows conduction down dramatically. A condition you may consider that this involves is MS; there are also motor nerve diseases (ALS being the most common).

    In terms of structure and how it is made that sounds a little too complicated for AS. However, as you correctly said in the PNS it is Schwann cells that are responsible, and Oligodendrocytes in the CNS.
Write a reply…


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: June 17, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Do you like sleeping in a cold room?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.