Pathophysiology
Clinical meaning
Breathing is controlled by the respiratory center in the medulla oblongata, which responds to changes in PaCO2, pH, and PaO2 via central and peripheral chemoreceptors. Normal breathing is regular with a rate of 12-20 breaths/min in adults. Abnormal patterns reflect underlying pathology: Kussmaul breathing (deep, rapid) indicates metabolic acidosis, Cheyne-Stokes (crescendo-decrescendo with apnea) suggests heart failure or brain injury, and Biot's breathing (irregular with apnea) indicates brainstem damage.