Emergency Medical Technician (EMT) Intermediate Practice Exam

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Study for the EMT Intermediate Exam. Access detailed flashcards and multiple-choice questions that come with hints and explanations. Prepare comprehensively for your EMT certification!

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What stimulates breathing in the hypoxic drive mechanism?

Increased carbon dioxide levels
Low arterial oxygen level
High acidity of the blood
High blood pressure

The correct answer is: Low arterial oxygen level

The hypoxic drive mechanism is a physiological response that stimulates breathing primarily in individuals with certain chronic respiratory conditions, such as COPD. In these patients, nerve chemoreceptors are less responsive to carbon dioxide levels due to chronic elevation of carbon dioxide in their blood. Instead, it is the low arterial oxygen levels that become the primary stimulus for breathing. When oxygen levels drop, these chemoreceptors send signals to the respiratory center in the brain to initiate breathing, helping maintain oxygen delivery to tissues. In contrast, increased carbon dioxide levels typically stimulate breathing via the central chemoreceptors in healthy individuals, while the acidity of the blood is more relevant in the context of metabolic or respiratory acidosis. High blood pressure does not directly impact the drive to breathe in the same way that low oxygen levels do. Therefore, low arterial oxygen level is the key trigger for the hypoxic drive, marking its significance in the respiratory response for patients with impaired respiratory systems.