The respiratory rate is driven by question 4 options: a. increased pco2, decreased ph, decreased po2. b. increased pco2, increased ph, decreased po2. c. decreased pco2, decreased ph, increased po2. d. decreased pco2, decreased ph, decreased po2.

The correct answer is a. increased pCO2, decreased pH, decreased pO2.

Respiration is stimulated by high levels of pCO2 in the blood which are registered by chemoreceptors in the medulla of the brain. Because of the excessive CO2 in the blood, the pH is falling and when this occurs, the respiratory rate is stimulated to increase. In the condition of hypoxia, the chemoreceptors are more sensitive to O2 than to CO2. As the O2 levels in the body drop, the respiratory drive is stimulated.