Lung Disease
L.O: to describe the effects of lung diseases
on lung function
Starter: Pulmonary TB is a disease of the
lungs. Describe the transmission and
course of infection of pulmonary TB. (5
marks)
Answers
Bacteria inhaled by person not immune
to it
Bacteria start to reproduce in upper lung
where plenty of oxygen
Usually in young
children
Primary
Infection
Immune system responds, phagocytes
arrive and ingest bacteria
Lymph nodes that drain area of lungs
become inflammed and enlarged –
Post-Primary Infection (may not
happen)
In healthy, more
resistant people
Few symptoms and the infection is
controlled, but some bacteria remain
Many years later bacteria re-emerge in
a second infection
More difficult to control. Lung tissue
damaged, scar tissue forms
Lung tissue and blood coughed
up,without treatment can fatally spread
throughout body
Disease
Pulmonary
Fibrosis
Asthma
Emphysema
Cause
Affect on lungs
Symptoms
Disease
Cause
Affect on lungs
Symptoms
Pulmonary Fibrosis
Exact cause unclear
– microscopic
injury/genetic
predisposition
Scar tissue
lengthens diffusion
pathway and alveoli
are less elastic
Shortness of breath
Chronic, dry cough
Pain in chest
Weakness and
fatigue
Asthma
Localised allergic
reaction
Bronchiole muscle
contracts,
constricting airways
so less oxygen can
enter lungs
Difficulty breathing,
Wheezing sound
when breathing
Tight feeling in
chest/Coughing
Emphysema
Almost always
smoking. Rarely air
pollution
Alveoli merge
together – more
space, less surface
area. Elasticity
reduced, exhalation
volume reduced
Shortness of breath
Chronic cough
Bluish skin
colouration
Lung diseases
The all disrupt lung function:
• Pulmonary TB (only infectious disease here)
– Bacteria destroy lung tissue - cavities and scars form
• Pulmonary fibrosis
– Scar tissue thickens diffusion path
– Reduces elasticity – lower volume of air exhaled
• Asthma
– Constricted airways reduce air taken in (inhalation affected)
• Emphysema
– Surface area of alveoli reduced
– Reduces elasticity – lower volume of air exhaled
Past Exam Q
Emphysema is another disease of the lungs.
People with emphysema may feel weak
and tired. Explain why. (5 marks)
Answers
Keyword Crossword
Think of keywords on lungs and apply them
to the crossword
A-D Cards
Which is an infectious disease?
A.Pulmonary tuberculosis
B.Asthma
C.Pulmonary fibrosis
D.Emphysema
A-D Cards
What is the main site of gas exchange in
lungs?
A.Trachea
B.Alveoli
C.Bronchi
D.Bronchioles
A-D Cards
Pulmonary ventilation =
A.Tidal wave X ventilation rate
B.Tidal volume X heart rate
C.Tidal volume / ventilation rate
D.Tidal volume X ventilation rate
A-D Cards
Which is not correct. During:
A.Inspiration the diaphragm flattens
B.Expiration the external intercostals relax
C.Inspiration the internal intercostals
contract
D.Expiration the diaphragm contracts
A-D Cards
Which is not a feature of Fick’s Law?
A.Surface area
B.Length of diffusion path
C.Water potential
D.Difference in concentration