If a transaction is made between the pons and medulla with intact vagi, respiration will become:
Regulatory centres of respiration: "Unlike in the hea, there is no single 'pacemaker' neurone responsible for initiating breathing. Instead, a group-pacemaker system exists in which groups of associated neurones generate regular bursts of neuronal activity. For breathing, the group pacemaker involves a complex interaction of at least six groups of neurones with identifiable firing patterns spread throughout the medulla, although concentrated in the region of the pre-Botzinger complex " - Nunn's respiratory physiology 8ed pg 52 DRG: contains mainly inspiratory neurons (I) and generations ramp signals VRG: contains both I and E neurons that emain almost totally inactive during normal quiet respiration A pneumotaxic center, located dorsally in the nucleus parabrachialis of the upper pons, transmits signals to the inspiratory area. The primary effect of this center is to control the "switchoff" point of the inspiratory ramp, probably by inhibiting apneustic centre Section A: Cut at upper pa of pons: Normal rhythmic breathing continues. Loss of voluntary breathe holding. If vagi are cut, increase in depth and slow breathing. Section B: Cut at midpons: Apneustic center (Ap) intact but pneumotaxic separated. Ap stimulates Inspiratory (I) neurons, which increase depth of breathing. Vagi cut: Arrest of respiration in maximum inspiratory phase (apneusis) interrupted by brief expiration. Section C: Cut at inferior poion of pons: All the pontine tissue is separated Vagi intact or cut: Irregular and gasping Section D: Cut below medulla: Complete transaction of brainstem: Stops all respiration (apnoea and death)
Apneustic
Irregular
Slow and deep
All of the above
Respiratory System