The primary direct stimulus for excitation of central chemoreceptors regulating ventilation is: (A) Increased H+, (B) Increased CO2, (C) Increased O2, (D) Decreased CO2
Answer is A. The main chemoreceptors involved in respiratory feedback are: Central chemoreceptors: These are located on the ventrolateral surface of medulla oblongata and detect changes in the pH of spinal fluid. Ref: guyton and hall textbook of medical physiology 12 edition page number:371,372,373