Question

(Because of the decreased influx of cations, the local nerve cell RMPs will be reset from -90mV to -120mV.) with the effect of numbing the skin in the area to be stitched.

1) Since the RMPs of the area nerve cells are now more positively charged, they are hypopolarized and therefore will conduct pain sensations very slowly or not at all.
2) Since the RMPs of the area nerve cells are now more negatively charged, they are hyperpolarized and therefore will conduct pain sensations very slowly or not at all.
3) Since the RMPs of the area nerve cells are now more negatively charged, they are hypopolarized and therefore will be so hyperactive that pain sensation will be negligible.
4) Since the RMPs of the area nerve cells are now more positively charged, they are hyperpolarized and therefore will conduct pain sensations very slowly or not at all.

Answer 1

Option 2 is correct because when nerve cells are hyperpolarized, their resting membrane potential is more negative, depressing the initiation of action potentials and reducing pain transmission.

Step-by-step explanation:

The correct response to the question on how the resting membrane potential (RMP) affects nerve cell conductivity and sensation is option 2: Since the RMPs of the area nerve cells are now more negatively charged, they are hyperpolarized and therefore will conduct pain sensations very slowly or not at all. Hyperpolarization of a neuron means that the membrane potential becomes more negative than the normal resting potential, making it less likely for an action potential to occur, thereby reducing the sensation of pain.

Local anesthetics like lidocaine work by blocking voltage-gated sodium (Na+) channels. Since these channels are critical for the rise in membrane potential that initiates an action potential (depolarization), their inhibition leads to a failure to transmit nerve impulses effectively, resulting in numbness.