Slides in this set
What is it? How is it caused?
Pulmonary fibrosis is a rare lung condition
that causes scarring of the lungs. It involves
the overgrowth, hardening and or scarring
of tissue because of excess collagen.
To diffuse respiratory gases, the linings of
the alveoli need to be thin.
The damage can be caused by many
different things such as airborne toxins in
the workplace, certain lung diseases and
even some types of medical treatments.
Idiopathic pulmonary fibrosis is rare,
affecting fewer than 10 in 10,000 people in
the UK. The condition mostly affects
middle-aged people aged 50 and over, and
is more common in men and those who are
How does fibrosis affect gas exchange in the
lungs? What does it do to the lungs?
Oxygen cannot diffuse into the blood as efficiently because the diffusion
pathway is longer and therefore the volume of air in the lungs is reduced as a
result. As well as this fibrosis also reduces the elasticity of the lungs, this then
makes it harder to expire and thus harder to ventilate the lungs.
· The relative rate of oxygen and carbon dioxide exchange across these thin
membranes depends upon diffusion and the solubility of the gases in the fluid
membrane. This is described by Fick's law.…read more
What are the symptoms? Why do they
result from the disease?
· Shortness of breath- due to the reduced volume in the lungs being occupied by
fibrous tissue. This means there in less air being taken in through inspiration. The
thickened epithelium of the alveoli also means that the diffusion pathway is
increased, making the diffusion of blood much slower. The loss of elasticity of
makes ventilating the lungs extremely difficult and makes it hard to maintain a
diffusion gradient across the exchange surface.
· Chronic, dry cough- occurs because the fibrous tissue cause and obstruction, the
body's reflex is to then try to get rid of the obstruction by coughing. As the tissue
cannot be removed the cough is `dry'.
· Pain and discomfort in the chest- this occurs because of the pressure and causes
damage from the mass of fibrous tissue in the lungs and further damage due to
· Weakness and fatigue- this results from the reduced intake of oxygen into the
blood. Therefore the release of energy by cellular respiration is reduced, leading to
· There is currently no treatment for pulmonary fibrosis. In some cases if
the patient is young and relatively healthy a lung transplant will be
· However, Oxygen therapy and pulmonary rehabilitation may help to
improve the daily lives of some patients with pulmonary fibrosis. Patients
can also help themselves by leading as healthy a lifestyle as possible. This
includes eating well, not smoking and exercising regularly.…read more