Consider the nerve fiber discussed in Example 19.10. Assume the fi ber is coated with a layer of myelin that is 100 nm thick. If the dielectric constant of myelin is the same as for a lipid layer, what is the time constant of this fiber? Ignore the gaps in the myelin sheath in Figure 19.41. These gaps are called nodes of Ranvier.

 

The myelin coating increases the thickness of the membrane, making the capacitance smaller. Myelin sheath Node of Ranvier 1 mm n Figure 19.41