The lungs are spongy organs that are made up of multiple tissue types that allow them to carry out their function of gas exchange. This organ system includes the following:
- The airways (starting from the trachea outside the lungs, to the bronchi, bronchioles, and ultimately the alveolar sacs)
- The blood vessels (the pulmonary arteries and its branches, the pulmonary veins and its branches, and most importantly, the pulmonary capillaries that are intimately associated with the alveoli and are the site of gas exchange)
- The interstitium/connective tissues that hold everything together, and the pleura (a thin layer of tissue that lines the outside of the lungs and the inside of the thoracic cavities with a small amount of lubricant fluid between them that allows the lungs to slide smoothly as they expand and contract with each breath)