Bronchi is the plural of bronchus, which is a passage way present in the lungs. The bronchus is an airway that allows air to move in and move out facilitating respiration. They are the extensions of the windpipe. The bronchi begins at the trachea (windpipe), and it branches into the main left bronchus and the main right bronchus. As they move into the lungs, they further branch out into lobar bronchi and bronchioles. The bronchioles further open out into tiny air sacs called alveoli. While the right main bronchus is wider and shorter, the left main bronchus is longer. The bronchi contain cartilage and have mucosal lining. This mucosal lining produces mucus in order to trap foreign particles that enter the lung and the bronchopulmonary segment. The smooth muscle that is present in the bronchi are controlled involuntarily. They expand and contract as per the messages of four nerve networks centered at the dorsal respiratory group in the medulla, ventral respiratory group in the medulla, pneumotaxic center in the nuclei of pons, and apneustic center in the nuclei of the pons. Though the process of expansion and contraction of the bronchi is involuntary, there are certain exceptions like voluntary breathing exercises, yawning, holding breath while swimming, blowing and others. The main function of the bronchi is to allow air in to exchange oxygen and to release carbon dioxide. Some common conditions of the bronchi include asthma, bronchitis, aspiration pneumonia, bacterial pneumonia, bronchospasm, bronchopulmonary dysplasia, bronchiolitis, and bronchiectasis. In people with diabetes, some uncommon complications of the respiratory system include bronchial obstruction, and pulmonary edema. Some common complications of diabetes involve obstructive sleep apnea, reduced lung function, and decreased levels of diffusing capacity for carbon monoxide, pulmonary fibrosis, and pneumonia. Damage to the lungs occurs in people with diabetes due to the fact that high blood sugar levels tend to stiffen the tissue of the lungs. Moreover, fat tissue present in the chest and the abdomen tends to restrict the lung capacity.