Mechanoreceptors and Breathing

Central respiratory control mechanisms regulate tidal volume and inspiratory and expiratory times to achieve adequate ventilation and gas exchange. Input signals emanate from chemoreceptors and from mechanoreceptors in the upper airways, lungs, and chest wall, with signals transmitted by the vagus nerve and spinal nerves. Respiratory muscle function may be assessed by direct measurement of neural activity, electromyography, or mechanical consequences (i.e., tidal volume, minute ventilation, and analysis of motion and pressures generated by specific muscles). Although it was previously believed that inspiratory muscles, including the diaphragm, might fatigue during inspiratory resistance loading, voluntary cessation of loading and carbon dioxide retention occur before muscle fatigue.^[210] Upper airway musculature may also be altered by inhaled anesthetics, thereby affecting evaluation of overall respiratory function.