Incorrect
Question 21
0/1 pts
1
A nerve signal moves down a myelinated neuronal axon with an initial speed, vi. We
may model the system as a combination of resistors and a capacitor as shown in the
diagram. Now, assume the distance between nodes of Ranvier (D) is reduced so, Df =
Di, and the resistivity of the axoplasm (pa) is halved so Pa,f = Pa,i. Assume
everything else is held constant. How will the signal velocity change? For this problem,
we may assume that resistance of the myelin sheath is much greater than the resistance
of the axoplasm and can thus be ignored, and the axon can be treated as a cylinder of
constant radius a.
D
Ra
a
RmTC
The nerve velocity will decrease by a factor of 2 (vf = vi/2)
The nerve velocity will decrease by a factor of 8 (vf = Vi/8)
The nerve velocity will not change.
The nerve velocity will increase by a factor of 4 (vf = 40)
The nerve velocity will increase by a factor of 8 (vf = 80;)