This document discusses electrolytes, including their definition, functions, normal ranges, and imbalances. The four main electrolytes covered are sodium, potassium, chloride, and bicarbonate. Sodium is important for nerve impulses, fluid balance, and acid-base regulation. Potassium influences neuron function, osmotic balance, and muscle contraction. Chloride impacts fluid balance and acid-base regulation. Bicarbonate maintains acid-base homeostasis. Imbalances like hyponatremia, hypokalemia, hypernatremia, and hyperkalemia are explained along with their causes and effects. Methods for electrolyte detection include flame photometry and ion-selective electrodes.