Output from higher brain centers can bypass both the DRG and VRG and go directly to _____,which controls the accessory muscles of respiration.

17. Which issues output to the VRG to adjust the respiratory rhythm?

18. This center bears the primary responsibility for generating the respiratory rhythm, but is influenced by several other centers.

19. Emotional states are integrated by ___, which generates an output that creates such respiratory variations as laughing and crying.

20. The pH of the cerebrospinal fluid is monitored by which of these brainstem centers?