Homework

• P.86-7 exam style questions

• Order a heart from butchers for dissection pig, next week day =

• Pig/ox (big one)• With atria and blood vessels on for dissection

please

Work for Tuesday 20th p1 or p2bring weds/fri lesson

• Read p88-9 (heart structure)• Make a list of bullet points on this• Do red p89 and mark• Read P.91 Valves (only)• Make a list of bullet points on this • Complete heart worksheet (answers behind desk in

library, already there)

• Homework for week = start to revise for mock exam. BRING REVISION TO 27th WITH HEART

3.1.4 Lung disease

FibrosisAsthma

Emphysema

Syllabus points

• Describe the effects of fibrosis, asthma, and emphysema on lung function

• Explain symptoms of diseases and conditions affecting the lungs in terms of gas exchange and respiration

What is asthma?Asthma is a chronic condition in which the airways occasionally narrow and become inflamed, limiting airflow.

Asthma causes difficulty breathing, wheezing and chest tightness, and can be mild or life-threatening.

Treatment is with bronchodilators, corticosteroids, or a combination of the two.

Asthma is triggered by a range of stimuli, such as allergens, dust, exercise, stress and infections.

COPD: emphysemaEmphysema is a gradual breakdown of alveolar walls and damage to terminal bronchioles and alveolar capillaries.

This reduces the efficiency of gas exchange, causing chronic breathlessness and hyperventilation.

Using this photo of healthy lung tissue (left) and emphysema lung tissue (right), can you explain why gas exchange is less efficient in emphysema?

Name the disease

1

2

3

http://www.abpischools.org.uk/lib/liInteractiveAnim/195/asthma_attack.swf

http://www.abpischools.org.uk/lib/liInteractiveAnim/205/salbutamol3.swf

COPD

• ChronicObstructivePulmonaryDisease

• includes chronic bronchitis and emphysema.• COPD leads to damaged airways in the lungs, causing

them to become narrower and making it harder for air to get in and out of the lungs.

• The word ‘chronic’ means that the problem is long-term.

Diagnosing COPDThere is no one single test for COPD. Diagnosis depends on taking into account a patient’s risk factors (e.g. whether they smoke, their age), their symptoms and clinical tests.

Testing the patient’s lung function using spirometry is essential. It can determine whether there is airway obstruction and can help exclude the possibility of other respiratory diseases, such as asthma or lung cancer.

Effect on lung function, gas exchange and respiration

Using cut out tabulate the information needed for each disease.

Include diagrams and examples where necessary

Lung diseasesFibrosis Asthma Emphysema

What happens

Symptoms

Causes

Effect on lung function/gas exchange

Effect on respiration

Disease fibrosis asthma emphysema

What happens

Scars thicken lung tissueDiffusion distance for gases increasedElasticity of alveoli reduced therefore difficult to breathe out so hard to maintain diffusion gradient

Localized allergic reactionHistamine released by bronchioles/bronchi causes airway lining to become inflamedMore mucus is secreted by the epithelial cellsMuscles around bronchioles contract to constrict airways

Lungs irreversibly damaged by smokeElastic tissue permanently strtched so alveoli not emptied properlyAlveoli burst so reduced surface area for gas exchange

Symptoms Short of breathChronic dry coughCough more to try to remove irritated lung tissuePain in chest due to tissue damageWeakness and fatigue – can’t get enough oxygen into the blood

Difficulty breathingWheezing soundsTight chestCough

Short of breathChronic coughBlue skin

Cause Unclear, microscopic lung injury/genetic susceptible

Genetic, air pollution, stress, chemicals in products, fewer allergens exposed to children

SmokingIndustrial e.g. mining

Effect on lung function

Reduced due to longer diffusion distance, reduced diffusion gradient

Resistance to air flow prevents concentration gradient being maintained

Reduced due to less surface area for gas exchange and reduced diffusion gradient as alveoli cannot empty efficiently

Effect on respiration

Less oxygen so less aerobic respiration in tissue. Less carbon dioxide taken away

Less oxygen so less aerobic respiration in tissue. Less carbon dioxide taken away

Less oxygen so less aerobic respiration in tissue. Less carbon dioxide taken away

Peak flow meters

• Human biology text p.125• Using a sterilised mouthpiece measure

your own peak flow• Why do asthmatics use peak flow as a

measure of their disease?

Plenary – which disease causes this effect?

1. Reduces surface area for gas exchange2. reduces diffusion gradient3. Less respiration in the tissues4. Scars in lung tissue5. Constricted bronchi6. Burst alveoli7. Dry Cough 8. Chronic cough9. Tight chest cough

1. Fibrosis,emphysema2. Fibrosis asthma3. All 34. Fibrosis5. Asthma6. Emphysema 7. Fibrosis 8. Emphysema 9. Asthma

Determining lung function