Chapter 12: Myelin sheath Flashcards
1
Q
What is a myelin sheath?
A
a spiral layer of insulation around a nerve fiber, formed by oligodendrocytes in the CNS and schwann cells in the PNS. It is made up of 20% protein and 80% lipid
1
Q
What is myelination?
A
the production of the myelin sheath. It begins in the fourteenth week of fetal development, yet hardly any myelin exists in the brain at the time of birth.
2
Q
PNS myelin
A
3
Q
CNS myelin
A
4
Q
node of ranvier
A
each gap between segments of the myelin sheath
5
Q
unmyelinated nerve fibers
A
