Myelination (FINAL)

Question 1

How does myelination increase the conduction velocity of an action potential?

Answer 1

Myelination increases conduction velocity via saltatory conduction

Question 2

How does the myelin sheath aid in saltatory conduction? How does this affect ion leakage and the capacitance of the axonal membrane?

Answer 2

It wraps around the axon, much like a fatty electrical insulator, preventing ion leakage (i.e., increased resistance) across the axonal membrane and reducing capacitance

Question 3

How do the Nodes of Ranvier contribute to saltatory conduction? How does this aid signal transmission?

Answer 3

Allowing the action potential to jump between the nodes, which ultimately accelerates signal transmission

Question 4

How does increased membrane resistance affect the spread of current?

Answer 4

Current spreads much farther

Question 5

How does decreased capacitance affect membrane charging and response?

Answer 5

Faster membrane charging and quicker response

Question 6

In what 3 ways is myelination advantageous to vertebrate nervous systems?

Answer 6

1) Faster communication

2) Smaller, more compact nerves = thin, high-capacity wiring in small space (essential for complex bodies and brains)

3) Energy efficiency b/c ion exchange, which requires energy, only occurs at the Nodes of Ranvier