<prompt> Emphysema pathologically involves beyond the-BronchiTerminal bronchioleRespiratory bronchioleAlveolar Sac  <response>: EmphysemaEmphysema is a condition of the lung characterized by abnormal permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of their walls and without obvious fibrosis.Destruction of walls is necessary to define emphysema. Enlargement of airspaces without destruction of their walls is termed overinflation, for example, the distention of airspaces that occurs in the remaining lung after unilateral pneumonectomy. 