Are muscles of inhalation tonic or phasic? What about muscles of exhalation? What are functions of the phasic muscles?

• A. Inhalation muscles are phasic; exhalation muscles are tonic; phasic muscles provide less proprioceptive input.
• B. Inhalation muscles are tonic; exhalation muscles are phasic; phasic muscles provide greater proprioceptive input and help prevent tonic muscles from becoming hypertonic.
• C. Inhalation muscles are tonic; exhalation muscles are tonic; phasic muscles have no special function.
• D. Inhalation muscles are phasic; exhalation muscles are phasic; phasic muscles cause hypertonicity.

Answer: (B)