1.4LUNG VOLUMES Tidal volume can be defined as the amount of air that moves into the lungs with each inspiration or the amount that moves out with each expiration. It is about 500 milliliters in an adult male. The inspiratory reserve volume is the extra volume of air that can be inspired over and above the normal tidal volume when the person inspires with maximal inspiratory effort, which is about 3000 milliliters. The maximum extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration is the expiratory reserve volume, which is usually about 1100 milliliters. And the air left in the lungs after a maximal expiratory effort is the residual volume averages to about 1200 milliliters. Some of the air breathed in simply fills respiratory passages but never reaches the gas exchange areas and is called dead space air. The space in the conducting zone of the airways occupied by gas that, does not exchange with blood in the pulmonary vessels is the respiratory dead space. The largest amount of air that can be expired after a maximal inspiratory effort is the forced vital capacity (FVC), which is often measured clinically as an index of pulmonary function. This is very useful in obtaining information …show more content…
Also, later in life smoking, occupational exposures, or accidents may damage the lungs. These abnormalities allow air pollutants to break through the lung's defences and result in respiratory diseases. Respiratory diseases are pathologies that affect the air passages, including the nasal passages, the bronchi and the lungs. They can be classified in many different ways as of the organ involved, the pattern or symptoms or the cause of the disease. However, the most common can be categorised under two broad types as acute infections, such as pneumonia and bronchitis, and chronic conditions such as asthma or chronic obstructive pulmonary