Which type of receptors regulate breathing in response to changes in hypoxemia?

• A. Centrally located chemoreceptors
• B. J-receptors
• C. Baroreceptors
• D. Peripheral chemoreceptors

Answer: (D)

The correct answer highlights the role of peripheral chemoreceptors in regulating breathing in response to changes in hypoxemia, which refers to low levels of oxygen in the blood. Peripheral chemoreceptors are primarily located in structures called the carotid bodies and aortic bodies. These receptors are highly sensitive to changes in the partial pressure of oxygen (PaO2) in the arterial blood.

When hypoxemia occurs, these peripheral chemoreceptors are activated and send signals to the respiratory centers in the brainstem. This process stimulates an increase in the rate and depth of breathing to enhance oxygen intake and restore normal oxygen levels in the bloodstream. The response to low oxygen is crucial, especially during situations such as high altitude exposure or respiratory illnesses.

The other types of receptors listed serve different physiological roles. Centrally located chemoreceptors respond primarily to changes in carbon dioxide levels and pH in the cerebrospinal fluid. J-receptors, also known as juxtapulmonary capillary receptors, are sensitive to pulmonary congestion and lung inflammation, leading to rapid shallow breathing or sensations of dyspnea rather than a direct response to hypoxemia. Baroreceptors are involved in the detection of blood pressure changes and do not have a direct role in oxygen regulation. Therefore,