Final answer:
Severe vomiting causes metabolic alkalosis by leading to the loss of hydrogen ions from the stomach. This, along with other factors like certain medications, can disturb the acid-base balance, resulting in a blood pH above 7.45, characterized by a primary bicarbonate excess.
Step-by-step explanation:
Severe vomiting can lead to metabolic alkalosis because it causes a loss of hydrogen ions and chloride ions, which are components of hydrochloric acid (HCl). This loss of acid from the stomach disturbs the acid-base balance, leading to an excess of bicarbonate in the blood which makes the blood too alkaline. In addition to vomiting, metabolic alkalosis can be exacerbated by the use of certain medications, such as diuretics, which further deplete potassium, and overuse of antacids.
Conditions such as Cushing's disease can also contribute to chronic metabolic alkalosis through increased urinary excretion of potassium, which is another way the body loses hydrogen ions. On the other hand, metabolic acidosis occurs when the blood is too acidic and is associated with an entirely different set of causes, including the buildup of organic acids or excessive loss of bicarbonate ions through diarrhea.