Briefly describe the general situation and function of respiratory system.

Respiratory system is the general name of the organs that exchange gas with the outside world. The function of the respiratory system is mainly to exchange gas with the outside world, exhale carbon dioxide, inhale fresh oxygen, and complete the elimination of gas. The respiratory system includes respiratory tract, nasal cavity, pharynx, larynx, trachea, bronchi and lungs.

Functions of the respiratory system:

1, respiratory function: the respiratory system completes the function of external breathing, that is, lung ventilation and lung ventilation;

2. Defense function: The defense function of respiratory system is realized through physical mechanism, chemical mechanism, cell phagocytosis and immune mechanism.

3. Metabolic function: the lung has metabolic function on the physiologically active substances, lipids, protein, connective tissue, reactive oxygen species and other substances in the lung;

4. Neuroendocrine function: There is a kind of cells with neuroendocrine function in lung tissue, called neuroendocrine cells or K cells, similar to argyrophil cells in intestine.