NBCRNA QOTW Practice Exam

Local anesthetics achieve their effect primarily by blocking sodium channels in nerve cells. When an action potential is initiated in a neuron, it typically involves a rapid influx of sodium ions through voltage-gated sodium channels, which leads to depolarization and the propagation of the nerve impulse. Local anesthetics work by binding to these sodium channels in their closed or inactive states, preventing sodium from entering the nerve cell. This inhibition disrupts the generation and transmission of electrical impulses along the nerve, effectively resulting in a loss of sensation in the targeted area.

By blocking sodium channels, local anesthetics alter the normal process of depolarization and repolarization of neurons, which is crucial for the propagation of pain signals. Without the ability to depolarize, the neurons cannot transmit signals to the central nervous system, thereby providing the desired anesthetic effect.

Other options, while related to the physiological context, do not accurately describe the primary mechanism of action of local anesthetics. For example, increasing nerve impulse transmission would have the opposite effect of anesthetic action, while vasodilation can actually be caused by certain local anesthetics but is not central to their primary anesthetic properties. Anesthetizing the bloodstream is not a correct description of how these agents work, as