Intensive Care Medicine (ICM) Practice Exam

Where are blood-gas chemoreceptors located?

1. Pons

2. Medulla

3. Aortic arch

4. Alveolar ducts

The correct answer is: Aortic arch

Blood-gas chemoreceptors play a crucial role in monitoring the levels of carbon dioxide, oxygen, and pH in the blood, which helps regulate respiratory activity. The primary locations of these chemoreceptors are classified into central and peripheral chemoreceptors. Central chemoreceptors, which primarily detect changes in carbon dioxide levels through pH changes in the cerebrospinal fluid, are located in the medulla. The peripheral chemoreceptors, which are sensitive to changes in arterial oxygen and carbon dioxide levels, are found in the carotid bodies (located at the bifurcation of the common carotid arteries) and the aortic bodies in the aortic arch. The aortic arch specifically houses these peripheral chemoreceptors, which respond to hypoxemia (low oxygen levels) and aid in stimulating respiratory drive. This makes it significant as a key site for the detection of systemic blood gas changes, particularly in the context of oxygen levels. Thus, the correct response is anchored in the critical role of the aortic arch in respiratory regulation through its peripheral chemoreceptors, emphasizing its primary function in monitoring blood gases and contributing to homeostasis.