myelin

Question 1

is myelin a lipoprotein? increases speed of what? prevents leakage of? layers with spaces between? impulses what from node to node? what’s smaller and slower?

Answer 1

lipoprotein

increases speed of conduction, large axons

• “insulation”
• prevent leakage of electric current

layers with spaces (nodes of Ranvier) between cells

impulse “jumps” from node to node

“unmyelinated” axons - smaller, slower

Question 2

white matter

regions of the brain and spinal cord containing what fibers?

Answer 2

regions of the brain and spinal cord containing dense collections of myelinated fibers

Question 3

gray matter

regions of the brain and spinal cord containing what fibers?

Answer 3

regions of the brain and spinal cord containing mostly nerve cell bodies and unmyelinated fibers

Question 4

demyelination disorders

progressive destruction of..in what? causes loss of? what types of paralysis? give example.

Answer 4

progressive destruction of myelin sheaths in CNS and PNS

causes loss of sensation and motor control

numbing or flaccid paralysis

eg: multiple sclerosis ~ demyelination and scarring