QS Study

Ramp Signal

The nervous signal transmits to the respiratory muscle mainly diaphragm, is not an instantaneous burst of an action potential. It’s not an Action potential. It works by the nervous emission of weak impulses which progressively amplify in a ramp manner for about 2 seconds. It rapidly ceases for 3 seconds afterward, which turns off the excitation of the diaphragm and allows for the elastic recoil of the chest wall and lungs to cause expiration. Expiration occurs in between the inspiratory ramp signals. This ramp allows for a balanced increase in volume entering lungs rather than inspiratory gasps. The ramping controls respiratory rate. The control of ramp also controls the depth of respiration so that in grave respiration ramp increases rapidly to fill the lungs rapidly. Also, the point at which ramp ceases abruptly determines the length of respiration. If it ceases after a long time, that reduces the frequency of breathing and vice versa.

Fig: Ramp Signal

In a normal person, it begins weakly and increases steadily in a ramp manner for 2 sec. Then it cleared abruptly for next 3 sec., which turn off the excitatory effect at the diaphragm. And due to elastic of the lungs and chest wall to cause expiration than inspiratory signal begins again for another cycle. This cycle repeats again and again with expiration occurs between. For this region, the inspiratory signal is a ramp signal.

Two ways in which inspiratory ramp is controlled:

  1. Control of the rate of increase of ramp signal.
  2. Control of the limiting point at which the ramp suddenly ceases.