Question

How do the pneumotaxic and apneustic centers control respiration?

		D. The pneumotaxic centers directly stimulate motor neurons, assisting the DRG during hyperpnea.
		C. Both apneustic and pneumotaxic centers adjust the output of the DRG and the VRG.
		A. The apneustic is sympathetic which will dilate airways, enhancing perfusion of alveoli with air.
		B. The pneumotaxic is sympathetic which will dilate airways, enhancing perfusion of alveoli with air.

Answer 1

Ans: D: The pneumotaxic centers directly stimulate motor neurons, assisting the DRG during hyperpnea.

Explanation

Respiratory motor outputs are related to the three major phases of the respiratory cycle (inspiration, postinspiration and late expiration). The pneumotaxic center (located in pons) controls both the rate and the pattern of breathing. The pneumotaxic center is responsible for limiting inspiration, providing an inspiratory off-switch. The apneustic center of the lower pons appears to promote inhalation by a constant stimulation of the neurons in the medulla oblongata. The apneustic center sends signals to the dorsal group in the medulla to delay the 'switch off', the inspiratory off switch (IOS) signal of the inspiratory ramp provided by the pneumotaxic centre. It controls the intensity of breathing, giving positive impulses to the neurons involved with inhalation.