Resp reg

e. They are specially important in providing the powerful expiratory signals to abdominal muscle during very heavy expiration f. This operates mainly during high level of pulmonary ventilation specially during heavy exercise

c. Stretch receptors mainly located muscular part of bronchi and bronchioles, send signals to the dorsal group when the lungs become overstretched. d. Hering breuer reflex also increases the rate of respiration as signals from pneumotaxic center.

The difference between peripheral and central effect of co2 is the rapid effect of stimulation of peripheral chemoreceptors compare to the central effect (5 times) as response to co2 at the onset of exercise.