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P A R T 1 0
Drugs acting on the respiratory system
Acute respiratory distress syndrome (ARDS) is char-
acterised by progressive loss of lung compliance and
increasing hypoxia. This syndrome typically results
from a severe insult to the body, such as cardiovascular
collapse, major burns, severe trauma or rapid depres-
surisation. Treatment of ARDS involves reversal of the
underlying cause of the problem combined with ventila-
tory support.
■■
Inflammation of the lower respiratory tract can result
in serious disorders that interfere with gas exchange,
including bronchitis and pneumonia.
■■
Obstructive disorders interfere with the ability to
deliver gases to the alveoli because of obstructions
in the conducting airways and eventually in the
respiratory airways. These disorders include asthma,
chronic obstructive pulmonary disease (COPD),
cystic fibrosis and respiratory distress syndrome
(RDS).
CHAPTER SUMMARY
■■
The respiratory system is composed of the upper
respiratory tract, which includes the nose, pharynx,
larynx and trachea, and the lower respiratory tract,
which includes the bronchial tree and the alveoli.
■■
The respiratory system is essential for survival; it
brings oxygen into the body, allows for the exchange
of gases and expels carbon dioxide and other waste
products.
■■
The upper airways have many features to protect the
fragile alveoli: hairs filter the air; goblet cells produce
mucus to trap foreign material; cilia move the trapped
material towards the throat for swallowing; the
blood supply close to the surface warms the air and
adds humidity to improve gas movement and gas
exchange; and the cough and sneeze reflexes clear
the airways.
■■
The alveolar sac is where gas exchange occurs across
the respiratory membrane. The alveoli produce
surfactant to decrease surface tension within the sac
and facilitate diffusion.
■■
Respiration is controlled through the medulla in the
central nervous system and depends on a balance
between the sympathetic and parasympathetic
systems and a functioning muscular system.
■■
Inflammation of the upper respiratory tract is seen in
many disorders, including the common cold, seasonal
rhinitis, sinusitis, pharyngitis and laryngitis.
KEY POINTS
■■
Inflammation of the lower respiratory tract can result
in serious disorders that interfere with gas exchange,
including bronchitis and pneumonia.
■■
Obstructive disorders interfere with the ability to
deliver gases to the alveoli because of obstructions
in the conducting airways and eventually in the
respiratory airways. These disorders include asthma,
chronic obstructive pulmonary disease (COPD),
cystic fibrosis and respiratory distress syndrome
(RDS).
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ONLINE RESOURCES
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