Which one of the following elements is needed in the human body to transfer electrical signals by nerve cells ?

Nerve cells, or neurons, transmit information via electrical impulses known as action potentials [1]. This process is fundamentally dependent on the movement of specific ions across the neuronal plasma membrane. The generation and propagation of these signals are primarily driven by voltage-gated sodium channels. During depolarization, these channels open to allow an influx of sodium ions (Na+) into the cell, which raises the membrane potential and triggers the impulse [4]. To maintain the necessary concentration gradients for these signals, the sodium-potassium pump (Na+/K+-ATPase) actively transports sodium ions out of the cell and potassium ions in, using energy from ATP [4]. While other ions like potassium and calcium are involved, sodium is the essential element for the initial rapid depolarization phase of the electrical signal transfer in the human nervous system [4].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > 6.1 ANIMALS – NERVOUS SYSTEM > p. 101
2. [4] https://www.sciencedirect.com/topics/neuroscience/nerve-cell-membrane-potential