7.8: The potential difference would increase (become more positive) rapidly.
7.9: It is becoming more negative.
7.10: The resting potential will be re-established.
7.11: Either it has not reached threshold stimulus or it is in its refractory period.
7.12: The frequency of action potentials goes from zero to many very rapidly.
7.13: It can tell the doctor whether the pain is coming from a myelinated or unmyelinated nerve.
7.14: The synapse is inhibitory. It opens potassium channels.