Question

question 3
which of the following is true?
a the myelin sheath inhibits the flow of electrical charges at nodes
b myelination will not influence the speed of conduction of action potentials
c the myelin sheath is a protein wrapping
d unmyelinated axons rest in invaginations of schwann cells or oligodendrocytes
e the myelin sheath does not electrically insulate the axons from one another

Explanation:

• Option A: The myelin sheath does not inhibit electrical charges at nodes. Nodes of Ranvier are unmyelinated regions where electrical charges flow.
• Option B: Myelination increases the speed of action potential conduction (saltatory conduction).
• Option C: The myelin sheath is made of lipids (not just proteins).
• Option D: Unmyelinated axons are embedded in invaginations of Schwann cells (in PNS) or oligodendrocytes (in CNS). This is a correct statement.
• Option E: The myelin sheath electrically insulates axons from one another.

Answer:

D. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes