Question

The brain integrates input from the peripheral and central chemoreceptors. A reduction in PO₂ decreases the threshold and increases the sensitivity to PCl₃?

Answer 1

Chemoreceptors in the brain and peripheral areas detect changes in carbon dioxide and hydrogen ion concentrations, influencing respiration.

Step-by-step explanation:

Chemoreceptors in the brain and peripheral areas sense concentration changes in substances like carbon dioxide (CO₂) and hydrogen ions (H+). These chemoreceptors stimulate the respiratory centers of the brain to control respiration. When the concentration of CO₂ increases, it diffuses across the blood-brain barrier and triggers central chemoreceptors, leading to increased respiration. Conversely, low CO₂ levels decrease respiration. Similarly, peripheral chemoreceptors sense changes in hydrogen ion levels, which affect respiration as well.

Peripheral chemoreceptors also play a critical role in monitoring blood oxygen levels, especially when they fall below approximately 60 mm Hg, prompting an increase in respiratory rate to restore oxygen levels. It is important to note that these chemoreceptors detect dissolved oxygen molecules and not oxygen that is bound to hemoglobin.