Inhalation begins with the contraction of the muscles attached to the rib cage; this causes an expansion in the chest cavity. Then takes place the onset of contraction of the diaphragm , which results in expansion of the intrapleural space and an increase in negative pressure according to Boyle's Law . This negative pressure generates airflow because of the pressure difference between the atmosphere and alveolus. Air enters, inflating the lung through either the nose or the mouth into the pharynx ( throat ) and trachea before entering the alveoli. [ citation needed ]
Asthma, the most common chronic childhood illness in the United States, is a breathing disease in which the airways are inflamed, making breathing difficult. Studies in older children and adults show that inhaled corticosteroids are the most effective long-term control medicine for persistent asthma. These medicines reduce airway swelling and help prevent asthma symptoms. Pediatricians and researchers have wondered for years whether it can also be used to prevent the disease if it's given early enough. A new study supported by NIH's National Heart, Lung and Blood Institute (NHLBI) shows that, while they can reduce breathing problems in pre-school-aged children at high risk for asthma, inhaled corticosteroids don't prevent the development of persistent asthma.
Legionellosis outbreaks can be difficult to identify, especially if people travel to a common location, are exposed to Legionella , and then return home before becoming sick. State and local health departments take the lead in investigating outbreaks and implementing control measures to remove Legionella from the water identified as the source of infection. CDC is only involved in legionellosis outbreak investigations when additional assistance is requested. State and local health departments are the best source of information for a specific outbreak.