MYELIN

MYELIN

Demyelination

• Demyelination is the deterioration of the myelin sheath insulating the nerves.
• Demyelination prevents nerves from being able to conduct messages to and from the brain. The effects of demyelination can occur very rapidly. For example in Guillain-Barre syndrome (GBS), a demyelinating inflammation of peripheral nerves, it may only take a few hours for symptoms to appear once myelin is under attack. However the most common demylinating disease is MS.

How can this affect one's Occupational function/performance?

Cause:

• Inflammation
• Infection with certain viruses
• Metabolic problems
• Loss of oxygen
• Physical compression

Symptoms:

• Memory problems
• Pain
• Loss of bladder and bowel control
• Fatigue
• Racing heart beat or palpitations

• Numbness
• Loss of reflexes and uncoordinated movements
• Poorly controlled blood pressure
• Blurred vision
• Dizziness

• Can be detrimental to ones sense of wellbeing in many different ways.
• People suffering will experience being held back in terms of their occupational function.
• A disorder resulting from demyelination would alter ones ability to perform daily tasks
• Thes tasks could bring meaning and purpose to their life.
• Would either lead to a significant decrease in their performance or in some cases a complete halt of these activites.

How is myelin produced?

• The production of myelin is called myelination.
• Myelination begins in infancy and continues into adulthood.
• Myelin particularly forms around the long shaft, or axon, of neurons.
• The myelin membranes originate from and are a part of the Schwann cells in the peripheral nervous system.

Myelination takes place through glial cells wrapping around the axons in a spiral fashion. The axons are originally embedded in these glial cells, and the cell's membranes extend to wrap the axon tightly and repeatedly.

In the peripheral nervous system the glial cell wraps around a single axon to insulate it, in the central nervous system a glial cell may wrap around several axons at once

What is myelin?

Thank you for listening!

References:

• Myelin is composed of about 40% water and the dry mass is composed of about 80% lipids and 20% protein.
• Myelin is a fatty material that coats, protects, and insulates nerves.
• Enables electrical impulses to be rapidly conducted, as it helps to stop the impulse from leaving the axon and increases electrical resistance, therefore enhancing signal conduction.
• Myelin decreases capacitance and increases electrical resistance across the cell membrane.
• Myelinated axons are white in appearance, hence reffered to as the "white matter" of the brain

Myelin Rebuilding. Web. 6 Apr. 2015.

Fraser-Thill, Rebecca. 'Definition Of Myelination'. About.com Parenting. N.p., 2015. Web. 6 Apr. 2015.

'How Nerve Cells Become Myelinated.'. Ngidd.eu. N.p., 2015. Web. 6 Apr. 2015.

Blumenfeld, Henrike. 'A Look At Myelin And Myelin-Related Disorders'. Serendip.brynmawr.edu. N.p., 2015. Web. 6 Apr. 2015.

Case-Lo, Christine. 'Demyelination: What Is It And Why Does It Happen?'. Healthline. N.p., 2014. Web. 6 Apr. 2015.

Siegel, A., & Hreday, N. (2010). Essential neuroscience (2nd ed.). Philadelphia, PA: Lippincott,

Williams and Wilkins.

Lundy-Ekman, L. (2013). Neuroscience: Fundamentals for rehabilitation (4th ed.). St. Louis:

Elsevier.

Omar Al-Hayek (S00162764) OTHY200 Friday 11am Tutorial 17/04/2015