Respiration

The primary respiratory center, consisting of the inspiratory and expiratory neurons, is located in the reticular core of the medulla oblongata (see Chapter 17 ). Although the other respiratory neurons distributed in the pons are believed to affect the activities of these neurons,^[31] this theory is undergoing modification.^[32] Various abnormal patterns of respiration (e.g., gasping, apneusis, irregular shallow respirations) are observed in laboratory animals and humans with brainstem lesions. In brain death, spontaneous respiration does not occur in patients even when arterial carbon dioxide partial pressure reaches 55 to 60 mm Hg. Mechanical stimulation of the carina to induce the cough reflex may be helpful in detecting residual functioning of the medullary respiratory neurons.