The element represented by the symbol 'Na' is sodium. Sodium is a chemical element with the atomic number 11 and is part of the alkali metal group in the periodic table. It is highly reactive and typically found in nature in combination with other elements, such as in table salt (sodium chloride). Sodium plays several important roles in the body, including regulating blood pressure, balancing fluids, and facilitating nerve function and muscle contractions. Due to its reactivity, sodium must be stored under oil or in an inert atmosphere to prevent it from reacting with moisture and oxygen.