What defines metabolic alkalosis?

Metabolic alkalosis is characterized by an increase in the bicarbonate (HCO3-) concentration in the blood, leading to a higher pH level than normal. This condition typically arises from either excessive loss of hydrogen ions or excessive retention of bicarbonate.

Bicarbonate acts as a buffer in the body, helping to maintain acid-base balance. When there is too much bicarbonate, it shifts the pH towards alkaline, resulting in metabolic alkalosis. This situation can occur due to various factors such as prolonged vomiting, which leads to the loss of hydrochloric acid from the stomach, or excessive ingestion of alkaline substances.

In contrast, the other options relate to processes that do not align with the definition of metabolic alkalosis. For instance, too much carbonic acid would indicate an acidosis condition, as would the presence of excess H+ ions. Likewise, excess CO2 production is associated with respiratory acidosis, where the increased carbon dioxide leads to a corresponding increase in carbonic acid. Thus, having too much bicarbonate is a clear hallmark of metabolic alkalosis.