The main functions are as follows:
1. Respiratory function The respiratory system completes the function of external breathing, that is, lung ventilation and lung ventilation. Pulmonary ventilation is the process of gas exchange between the lungs and the external environment, and pulmonary ventilation is the process of gas exchange between alveoli and pulmonary capillaries. Respiratory physiology is very complex, including processes such as ventilation, ventilation, respiratory power, blood transport, and respiratory regulation.
2. Defense function The defense function of the respiratory system is through physical mechanisms (including nasal heating and filtration, coughing, sneezing, bronchoconstriction, cilia movement, etc.), chemical mechanisms (such as lysozyme, lactoferrin, protease inhibitors, antioxidant free glutathione and superoxide dismutase, etc.), phagocytosis (such as alveolar phagocytes and polymorphonuclear granulocytes, etc.) and immune mechanisms (B cells secrete antibodies, mediate delayed-type allergic reactions, and kill microorganisms) and so on.
3. Metabolic function The lung has a metabolic function for substances such as physiologically active substances, lipids, proteins, connective tissue and reactive oxygen species in the lungs. Certain pathological conditions can lead to metabolic abnormalities in the pulmonary circulation, which may lead to the exacerbation of pulmonary disease or the development of systemic disease.
4. Neuroendocrine function There is a kind of cell with neuroendocrine function in the lung tissue, called neuroendocrine cell or K cell, which is similar to the argentophilic cell in the intestine. Therefore, benign or malignant tumors originating from this cell are often clinically Demonstrated abnormal neuroendocrine function, such as hypercortisolism, hypertrophic bone disease, hypersecretion of ADH, and adult gynecomastia.