what is the difference between upper and lower respiratory tract
Respiratory tract The respiratory tract is divided into the upper airways and lower airways. The upper airways or upper respiratory tract includes the nose and nasal passages, paranasal sinuses, the pharynx, and the portion of the larynx above the vocal folds (cords). The lower airways or lower respiratory tract includes the portion of the larynx below the vocal folds, trachea, bronchi and bronchioles. The lungs can be included in the lower respiratory tract or as separate entity and include the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.[citation needed]
Lower respiratory tract infection There are a number of symptoms that are characteristic of lower respiratory tract infections. The two most common are bronchitis and cancer and edema.[3] Influenza affects both the upper and lower respiratory tracts.
United States House of Representatives The United States House of Representatives is the lower chamber of the United States Congress. The Senate is the upper chamber. Together they compose the legislature of the United States.
Vein Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.