Control of the diameter of the respiratory passages depends upon
A) sympathetic stimulation only.
B) parasympathetic stimulation only.
C) somatomotor stimulation only.
D) both parasympathetic and sympathetic levels of stimulation.
E) sensory receptors sensitive to changes in lung ventilation.

Question

Quizplus · Accepted Answer

Control of the diameter of the respiratory passages depends on both parasympathetic and sympathetic levels of stimulation. The sympathetic nervous system causes bronchodilation (widening of the airways) while the parasympathetic nervous system causes bronchoconstriction (narrowing of the airways). Therefore, a balance between the two is necessary for optimal control of the diameter of the respiratory passages.

Control of the Diameter of the Respiratory Passages Depends Upon