Exam 1: The Cerebrum & its main features

the cerebral cortex (location? Main characteristics? Made up of?)

• aka gray matter

• contains neurons (cell bodies and dendrites) and is found on the brain’s surface

white matter (location? Main characteristics? Made up of?)

• forms deeper layers

• contains axons (nerve fibers), which are myelinated

Why is white matter white?

due to the presence of myelin, a fatty insulating layer that surrounds nerve fibers (axons)

What is myelin?

• Consists of lipid (fat, cholesterol) layers surrounding axons

• insulates axons from ions in the CNS fluid, facilitating impulse propagation

• made of oligodendrocytes

What are oligodendrocytes?

A type of glial cell that forms myelin; provides myelin sheaths to multiple axons

What is an example of demyelinating, inflammatory conditions affecting the white matter?

• Multiple sclerosis is a disorder of the white matter

• It’s a demyelinating, inflammatory condition that is considered to be autoimmune in origin

• Essentially, the myelin sheath is damaged, which then slows down the propagation of electrical impulses down the axon

• MS symptoms can vary depending on the location of the lesions and may include visual disturbances, muscle weakness, coordination problems, and other issues