Physiological control of respiration

Abstract

Respiration involves the inward and outward movement of air into the lungs. This process facilitates gaseous exchange. The rate of respiration therefore regulates the partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) in the blood. Spontaneous respiration occurs as a result of rhythmic discharge of motor neurons innervating respiratory muscles. Nerve impulses from the brain are responsible for this rhythmic discharge. The rhythmic contraction and relaxation of respiratory muscles alternatively fill the lungs during inspiration and empty them in expiration. This rhythmic discharges from the brain are regulated by changes in arterial PaO2, PaCO2 and hydrogen ion (H+) concentration, which is called the chemical control of respiration.