Lung DiseaseLung DiseaseL.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)

AnswersAnswers

Bacteria inhaled by person not immune to it

Bacteria start to reproduce in upper lung where plenty of oxygen

Immune system responds, phagocytes arrive and ingest bacteria

Lymph nodes that drain area of lungs become inflammed and enlarged –

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

Primary Infection

Post-Primary Infection (may not happen)

Usually in young children

In healthy, more resistant people

Disease Cause Affect on lungs Symptoms

Pulmonary Fibrosis

Asthma

Emphysema

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 breathChronic, dry coughPain in chestWeakness and fatigue

Asthma Localised allergic reaction

Bronchiole muscle contracts, constricting airways so less oxygen can enter lungs

Difficulty breathing, Wheezing sound when breathingTight 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 breathChronic coughBluish 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 QPast Exam QEmphysema is another disease of the lungs.

People with emphysema may feel weak and tired. Explain why. (5 marks)

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Keyword CrosswordKeyword 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