Pulmonology and Critical Care

Lung Anatomy & Development

Anatomically, the lung has an apex, three borders, and three shells. The apex lies above the first caricature. The three borders include the anterior, posterior, and inferior borders. The anterior border of the lung corresponds to the pleural reflection, and it creates a cardiac notch in the left lung. Development of the lower respiratory tract begins on day 22 and continues to form the trachea, lungs, bronchi, and alveoli. The process divides into five stages embryonic, mock glandular, canalicular, saccular, and alveolar stage. The lungs are the major organs of the respiratory system, and are divided into sections, or lobes. The right lung has three lobes and is slightly larger than the left lung, which has two lobes. The lungs are separated by the mediastinum. This area contains the heart, trachea, oesophagus, and numerous lymph bumps.