SISTEMUL RESPIRATOR

SISTEMUL RESPIRATOR

The respiratory system is responsible for supplying oxygen to the blood and expelling waste gases, of which carbon dioxide is the primary constituent, from the body. The upper structures of the respiratory system are combined with the sensory organs of smell and taste (in the nasal cavity and the mouth) and the digestive system (from the oral cavity to the pharynx). At the pharynx, the specialized respiratory organs diverge into the airway. The larynx, or voicebox, is located at the head of the trachea, or windpipe. The trachea extends down to the bronchii which branch off at the trachial bifurcation to enter the hilus of the left or right lung. The lungs contain the narrower passageways, or bronchioles, which carry air to the functional unit of the lungs, the alveoli. There, in the thousands of tiny alveolar chambers, oxygen is transferred through the membrane of the alveolar walls to the blood cells in the capillaries within. Likewise, waste gases diffuse out of the blood cells into the air in the alveoli, to be expelled upon exhalation. The Diaphragm, a large, thin muscle below the lungs, and the intercostal and abdominal muscles are responsible for contracting and expanding the thoracic cavity to effect respiration. The ribs serve as a structural support for the whole thoracic arrangement, and pleural membranes help provide lubrication for the respiratory organs so that they are not chafed during respiration.