Respiratory centre controls the rate of respiration. Respiratory centre is located in medulla oblongata and pons. It has the following components (i) inspiratory area - connected to inspiratory muscles, (ii) Pneum otaxic area, (iii) Expiratory area, (iv) chemosensitive area. Chemoreceptors located on carotid and aortic bodies are sensitive to carbon dioxide levels in arterial blood. They send information to respiratory centre. Oxygen does not have a significant direct effect on the respiratory centre of the brain.