Final answer:
Tachypnea is a condition characterized by rapid breathing, which differs from hyperpnea (increased breathing due to oxygen demand) and hyperventilation (excessive ventilation leading to altered blood gases).
Step-by-step explanation:
Tachypnea is a medical term used to describe a condition of rapid breathing. It is the body's response to various conditions and is characterized by a higher than normal breathing rate. In contrast to hyperpnea, which is an increased rate and depth of ventilation due to an increase in oxygen demand like during exercise, tachypnea does not necessarily correspond to the oxygen needs of the body and can be a symptom of various health issues. On the other hand, hyperventilation is when the rate of ventilation exceeds the metabolic demand, and this can cause low blood carbon dioxide levels and high blood pH (alkaline condition), unlike tachypnea which does not directly affect blood gas values unless it is part of a pathological state.