How do electrolyte imbalances affect nerve function?

Electrolyte imbalances significantly disrupt nerve function because the nervous system relies on the precise distribution of ions—such as potassium ($K^{+}$), sodium ($N{a}^{+}$), and calcium ($C{a}^{2+}$)—across the neuronal membrane to generate and transmit electrical signals.

• Membrane Potential: The resting membrane potential of a neuron (typically $-60$ to $-75$ mV) is maintained by the concentration gradients of these ions. Because the membrane is semipermeable, changes in the concentration of ions—particularly $K^{+}$—directly alter the potential difference across the membrane, affecting a neuron's ability to polarize, depolarize, or hyperpolarize.12
• Signal Transmission: The release of neurotransmitters at the synapse is strictly dependent on the presence of extracellular $C{a}^{2+}$. When a nerve impulse depolarizes the presynaptic terminal, voltage-dependent calcium channels open, allowing $C{a}^{2+}$ to flow inward. This influx is essential for the exocytosis of synaptic vesicles; thus, an imbalance in calcium levels can directly impair communication between neurons.3
• Impulse Regulation: Various potassium channels regulate the duration and frequency of nerve impulses. For example, some channels are activated by intracellular $C{a}^{2+}$ to slow repetitive firing, while others manage repolarization. Disruptions to these ionic balances interfere with these regulatory mechanisms, potentially leading to abnormal neuronal firing patterns.45