The diaphragm is the flat, dome-shaped muscle located at the base of the lungs and thoracic cavity.
The parasympathetic system causes bronchoconstriction, whereas the sympathetic nervous system stimulates bronchodilation.
Reflexes such as coughing, and the ability of the lungs to regulate oxygen and carbon dioxide levels, also result from this autonomic nervous system control.
The right lung is shorter and wider than the left lung, and the left lung occupies a smaller volume than the right.
The cardiac notch is an indentation on the surface of the left lung, and it allows space for the heart (Figure 1). Each lung is composed of smaller units called lobes. The right lung consists of three lobes: the superior, middle, and inferior lobes.
A pulmonary lobule is a subdivision formed as the bronchi branch into bronchioles.
Each lobule receives its own large bronchiole that has multiple branches.The apex of the lung is the superior region, whereas the base is the opposite region near the diaphragm. The left lung consists of two lobes: the superior and inferior lobes.A bronchopulmonary segment is a division of a lobe, and each lobe houses multiple bronchopulmonary segments.An interlobular septum is a wall, composed of connective tissue, which separates lobules from one another.The blood supply of the lungs plays an important role in gas exchange and serves as a transport system for gases throughout the body.This blood supply contains deoxygenated blood and travels to the lungs where erythrocytes, also known as red blood cells, pick up oxygen to be transported to tissues throughout the body.The pulmonary artery is an artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli.The pleural cavity is the space between the visceral and parietal layers.The pleurae perform two major functions: They produce pleural fluid and create cavities that separate the major organs.Each segment receives air from its own tertiary bronchus and is supplied with blood by its own artery.Some diseases of the lungs typically affect one or more bronchopulmonary segments, and in some cases, the diseased segments can be surgically removed with little influence on neighboring segments.