Chapter 22, Problem 22.1PS

The Truth About Nerve Cells. For each of the following statements, indicate whether it is true of all nerve cells (A), of some nerve cells (S), or of no nerve cells (N).

(a) Axonal endings are in direct contact with the cells they innervate.

(b) The resting membrane potential of the axonal membrane is positive.

(c) Nodes of Ranvier are found at regular intervals along the axon.

(d) The resting potential of the membrane is much closer to the equilibrium potential for potassium ions than to that for sodium ions because the permeability of the axonal membrane is much greater for potassium than for sodium.

(e) Excitation of the membrane results in a transient increase in its permeability to sodium ions.

(f) The electrical potential across the membrane of the axon can be easily measured using electrodes.

(g) Calcium elevation stimulates release of neurosecretory vesicles containing serotonin.