Asthma

– results in contraction of smooth muscle that surrounds airways – makes breathing difficult

– allergic reaction

– treat with bronchodilators – causes airways to dilate (increase in diameter)

Bronchitis

– inflammation of bronchial lining + overproduction of mucous and frequent coughing

– related to smoking and other irritants (air pollution etc)

– increased mucous production – blocks airways and reduces respiratory efficiency

– can treat with bronchodilators

Emphysema

– associated with chronic bronchitis

– difficult for air to pass through and reach alveoli

– cilia no longer work – do not filter debris – debris builds up in air tubes – causes constriction of bronchioles – less air gets to alveoli

– air pressure builds up and lungs appear inflated -walls of alveoli tear and become damaged – decreases surface area for gas exchange – breathing rate increases to compensate – heart must also work harder than normal

Cystic Fibrosis

– autosomal recessive genetic disorder

– abnormally thick mucous blocks airways – not easily removed by cilia

– excess mucous leads to recurrent lung infections – persistent coughing, wheezing

Environmental Hazards

Asbestos

– used to insulate buildings

– can lead to lung cancer

Silica – major component of rocks and soil

– irritates respiratory tract

Smoking

– cilia stop beating

-increased mucous production

– cancer

– second hand smoke has higher concentration of substances than first hand smoke

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