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
