Science & Technology in Action

6th Edition

Diseases Of The Lungs

Teva Ireland

Jnr Science Cert
The human respiratory system and the function of the lungs in gaseous exchange with the blood is described in this lesson. Respiratory problems that impede proper functioning of the system are discussed. Some remedies are described including the use of inhalants to relieve lung congestion.
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Lesson excerpt

Lung Diseases
The lungs are a pair of organs located in the thoracic cavity. Their primary function is gaseous exchange, i.e. to get oxygen into and carbon dioxide out of the blood. Air is drawn in through the nose where it is filtered by hairs and mucus to remove dust, bacteria and viruses. As it passes through the nasal sinuses it is also warmed. The surface of the airways is covered bymucusproducing cells which trap anything that has not been filtered by the nose. Cilia [small hair like projections] waft the mucus up out of the lungs to the pharynx where it is normally swallowed. Any micro-organisms it contains are killed by the acid conditions in the stomach. About 1.5 litres ofmucus are produced daily. Anything that reduces the movement of air into or out of the lungs reduces the availability of oxygen to the body, with a resulting decrease in energy due to a decrease in respiration.

Bronchodilation, as the name suggests, is the widening of the bronchi when the smooth muscle surrounding the bronchi relaxes, allowing easier movement of air into and out of the lungs. This is brought on naturally by exercise or by the production ofadrenalin the "fight or flight hormone", noradrenalin has a similar effect.

bronchoconstriction, on the other hand, is the narrowing of the bronchi in the lungs due to any or all of the following: the contraction of surrounding smooth [involuntary] muscle or an accumulation of thick, difficult to expel mucus, which effectively blocks the bronchial tubes or inflammation of the bronchial tissue.

True or False?

  1. Emphysema is a curable disease. false
  2. The nasal sinuses warm and filter air entering the lungs. false
  3. Bronchoconstriction is a narrowing of the airways. false
  4. Asthma is a chronic disease. false
  5. Exercise does not cause asthma. false
  6. Only smokers suffer from bronchitis. false
  7. Preventer medication is short acting and need only be taken once. false
  8. Mucolytics make it easier to expel mucus from the lungs. false
  9. Steroids suppress the body’s immune system. false
  10. Inhalers are a very recent development in administering drugs. false