gázcsererendszere
A gázcsererendszere, vagyis a respiratory system, is the biological system responsible for the intake of oxygen and the expulsion of carbon dioxide, essential processes for cellular respiration and organismal survival. In humans and most terrestrial animals, this system comprises the lungs and associated airways, including the nose, pharynx, larynx, trachea, and bronchi. The lungs are the primary organs where the exchange of gases occurs between the inhaled air and the blood. This exchange takes place in tiny air sacs called alveoli, which are surrounded by a dense network of capillaries. Oxygen from the inhaled air diffuses across the thin alveolar and capillary walls into the bloodstream, where it is transported to the body's tissues. Simultaneously, carbon dioxide, a waste product of cellular metabolism, diffuses from the blood into the alveoli to be exhaled. Breathing, or ventilation, is the mechanical process that drives this gas exchange, involving the coordinated action of the diaphragm and intercostal muscles to expand and contract the chest cavity, drawing air in and pushing it out. Other organisms, such as aquatic animals, have different respiratory systems, like gills, which are adapted to extract dissolved oxygen from water. Even plants have a form of gas exchange, primarily through pores called stomata on their leaves, to take in carbon dioxide for photosynthesis and release oxygen. The efficiency and complexity of gázcsererendszere vary greatly across the diversity of life, reflecting adaptations to different environments and metabolic needs.