Control of breathing, diseases and Laboratory work 3

The respiratory centre is in the medulla oblongata; its impulses rhythmically contract the intercostal muscles and diaphragm. The centre is sensitive to carbon dioxide in blood: if it rises, breathing becomes faster and deeper. Breathing can also be changed voluntarily (cerebral cortex), but cannot be held for very long. Sneezing and coughing are protective reflexes: they clear dust and mucus from the airway. Respiratory infections (colds, influenza, tonsillitis, tuberculosis) spread by droplets; a sick person should rest at home, cover mouth and nose with a tissue or elbow when sneezing, wash hands with soap and air the room. Tuberculosis is a curable disease caused by mycobacteria; with long cough, weight loss or weakness see a doctor, and vaccination and timely treatment are important. Allergy is a strong reaction to dust, pollen or some foods; if breathing becomes difficult call 103 at once and get adult help; treatment is decided by a doctor. Smoking: smoke has thousands of chemicals, including cancer-causing ones, and damages lungs and vessels. According to WHO tobacco causes more than 8 million deaths a year; e-cigarettes are also not harmless for a young body. The best choice is never to start.