breathing

breathing is a part of the nutrition function. by breathing we obtain the oxygen our cells need to work. we also excrete the carbon dioxide our cells produce as a residues.

we breathe with our respiratory system which includes the lungs and airway.

the airway : are the tubes that connect the exterior of the body with the lungs. there are nasal passages , the pharynx, the larynx, the trachea ,   the bronchial and the bronchioles.

lungs : are two organs similar to sponges which contain the alveoli . there are situated in the  thorax and in the diaphagm