Topic 3: Exchange: The effecf of lung disease on humans

Total lung capacity

The maximum volume of air the lungs can hold. Lung volume following a maximum inhalation.

Tidal volume

The volume of air breathed in or out during a normal breath

Expiratory reserve volume

The amount of air available to possibly exhale following a normal exhalation

Inspiratory reserve volume

The amount of space available to fill following a normal inhiliation

Residual volume

The volume of air that always remains in the lungs, even after a maximal exhalation

Restrictive lung disease

Make it difficult to fully breathe in (affects elastic tissue). Severely reduces FVC as breathing in is difficult but FEV1 is less affected because breathing out is still normal. E.g. fibrosis

Obstructive lung disease

Make it difficult to breathe out as Airways are blocked. FVC and FEV1 are both much lower than normal. E.g. asthma.

Airways become inflamed due to an allergic reaction to inhale substances such as pollen or dust

Wheezing, tight chest, shortness of breath (can be relieved by inhaler which causes bronchioles muscles to relax. Smooth lining the bronchioles contract and lots of mucus is produced.

Emphysema – disease caused by foreign particles (from smoking or long-term exposure to air pollution) being trapped in alveoli: inflammation→ Fergus sites produce enzymes → breaks down and lasting and Alveoli walls

Shortness of breath and wheezing

Fibrosis – formation of scar tissue in the lungs after infection or breathing in substances like asbestos

Dry cough, shortness of breath, chest pain, fatigue, and weakness

Tuberculosis- caused by bacteria inhaled by droplet infection. Micro forges build a wall around the bacteria in the Alveoli forming small hard lumps called tubercules. Bacteria remain alive but dormant. Eventually the infected tissue dies damaging the alveoli. As a result of the immune system response fibrosis also occurs

Cough (coughs up mucus and blood) shortness of breath and fatigue

Effect of smoking on the lungs

• Airways on narrowed/blocked

• Excess mucus in airway

• Inflammation of airways

• Elasticity is lost/scar tissue builds up due to infection

Correlation

A link or relationship between two things that happen

Risk factors for long disease, referring to chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis

1. Smoking – 90% of people suffering from COPD are, or have been, heavy smokers

2. Air pollution – pollutant particles and gases (e.g. sulphur dioxide) increase the likelihood of COPD, especially in areas of heavy industry

3. Genetic make-up – some people are genetically more likely to get lung diseases, others less so, this explains why some lifelong smokers never get lung disease while others die early

4. Infection – people who frequently get other chest infections also show a higher incidence of COPD

5. Occupation – people working with harmful chemicals, gases and dust that can be inhaled have an increased risk of lung disease

Prove that smoking is the cause of early death in smokers the correct scientific process needs to be followed. There are three main stages:

1. Established a hypothesis to try to explain the correlation; this should be based on current knowledge

2. Design and perform experiments to test the hypothesis

3. Establish the causal link and formulate theories to explain it