Dietary Management for Lung Diseases

Author: Chief Editor: Chen Huizhong et al
Publisher:
Publish Date: 1997-09-01
Features: Synopsis Based on the traditional theory of "food and medicine share the same origin," this book systematically introduces the basic knowledge and dietary adjustment methods for 18 common lung diseases, such as colds, tracheitis, bronchitis, asthma, emphysema, whooping cough, bronchiectasis, pleurisy, tuberculosis, and lung cancer. It also recommends over 900 simple and practical medicinal diet recipes and dietary therapy methods. The text is easy to understand, rich in information, and suitable for patients with lung diseases and grassroots medical personnel to read and reference. Excerpt:
② Pharynx. It is a slightly flattened funnel-shaped tube composed of mucous membrane and pharyngeal muscles. It connects above to the nasal cavity and below to the larynx. It can be divided into the nasopharynx, oropharynx, and hypopharynx, serving as a common passage for both the respiratory and digestive systems. In addition to swallowing and breathing functions, the pharynx is also an important resonator for speech, assisting in vocalization. The pharynx contains abundant lymphoid tissue, forming the pharyngeal lymphatic ring with structures like the tonsils, which can defend against bacterial invasion of the pharynx. This function is more pronounced in early childhood.
③ Larynx. The larynx connects above to the hypopharynx and below to the trachea, serving as both a respiratory passage and an organ for speech. Its framework is mainly composed of the epiglottis cartilage, thyroid cartilage, and cricoid cartilage. Within the laryngeal cavity, there is one vocal cord on each side, and the space between the vocal cords is called the rima glottidis. During breathing or speech, the epiglottis opens to allow free air passage; during swallowing, the epiglottis automatically closes to prevent food from entering the trachea.
(2) Lower Respiratory Tract: The lower respiratory tract includes the trachea, left and right main bronchi, and their branches (lobular, segmental, subsegmental bronchi, bronchioles, and terminal bronchioles). Its primary function is as a pathway for gas exchange.
2. What are the structures and functions of the lungs? The lungs are located in the pleural cavity, cone-shaped, and the right lung is slightly larger than the left. Each lung has a lung apex, a lung base, and two sides. The lung apex reaches above the clavicle, the anterior part of the lung base is higher than the back, and the convex outer side adjacent to the ribs is the convex outer side. The inner or mediastinal side, called the hilum, is where the bronchi, blood vessels, and nerves enter and exit. The oblique fissure of the parietal pleura divides the left lung into upper and lower lobes, while the right lung has an additional horizontal fissure dividing it into upper, middle, and lower lobes. The lobes are further divided into pulmonary segments (the right lung has 3 lobes and 10 segments, while the left lung has 2 lobes and 8 segments), which are cone-shaped with their tops at the hilum and separated by small amounts of connective tissue. Each segment is composed of many pulmonary acini, which are the basic units of the lungs, varying in size and cone-shaped, with their tips pointing toward the hilum and bases toward the lung surface, separated by thin layers of connective tissue containing abundant blood and lymphatic vessels. The pulmonary acini are formed by the branching of bronchioles below the terminal bronchioles and corresponding lung tissue, and are classified in order of the amount of lung tissue they include into secondary pulmonary acini, alveolar sacs, and primary pulmonary acini.
(1) Secondary Pulmonary Acini: Secondary pulmonary acini are small lung tissues surrounded by connective tissue, irregularly shaped polyhedrons containing 30–50 primary lobules, with a diameter of 1 cm to 2.5 cm.
(2) Alveolar Sac: Alveolar sacs are the lung tissues supplied by the terminal bronchioles. Their outer capsule is incomplete, the submucosal tissue gradually degenerates, and it is directly connected to the lung connective tissue. The alveolar sacs contain respiratory bronchioles, alveolar ducts, and alveoli, which are the sites of gas exchange.
(3) Primary Pulmonary Acini: Primary pulmonary acini are lung tissues supplied by the terminal respiratory bronchioles. Their range is very small, and even if they become consolidated, they are difficult to be identified on X-ray images.
(4) Respiratory Bronchioles: Respiratory bronchioles have an average of 3 levels (ranging from 2 to 7) of continuous branching. The ciliated cuboidal cells on their surface gradually transform into flattened squamous cells with fewer or no cilia, and goblet cells significantly decrease or disappear, while Clara cells remain distributed. The walls of the bronchioles begin to show alveoli, and the number of alveoli increases with each branching level. The total number of airways from the trachea to the terminal branch of the respiratory bronchioles is estimated to be over 200,000.
(5) Alveolar Ducts: From the end of each respiratory bronchiole, there are an average of 3 levels (ranging up to 9) of serial short alveolar ducts. At this stage, the smooth muscle in the walls disappears, and the ducts are fully alveolarized. Below the alveolar ducts, there is almost no wall, but the closely packed alveoli are interconnected by fine muscle fibers, collagen fibers, and elastic fibers.