AIIMS 2018 Biology Nerve Impulse Conduction MCQ Question

During the conduction of a nerve impulse, also known as an action potential, Na⁺ ions move into the axoplasm through voltage-gated sodium channels, causing depolarization of the neuron. This influx of Na⁺ is essential for the rapid transmission of the nerve signal. In contrast, K⁺ ions (option C) move out of the axoplasm during repolarization, while Na⁺ moving out (option B) does not occur during the initial phase of the action potential. Ca²⁺ ions (option D) are involved in neurotransmitter release at synapses but are not directly responsible for the conduction of the nerve impulse along the axon.