Lung Disease- Defensive mechanisms

Question 1

What are the defense mechanisms for the lungs?

Answer 1

• Nose- hair filters air- size dependent
• Mucus- Mucociliary clearance
• Cough (reflex) remove substances from airways
• Immune system

Question 2

What is mucociliary clearance?

Answer 2

Defends the lungs against inhaled pathogens
Mucus layer on ciliated epithelium
Goblet cells in the conducting airway secrete mucus
Mucus traps pathogens and foreign material

Question 3

How is mucus moved from the lungs?

Answer 3

By ciliated cells

Question 4

What is the mucociliary escalator?

Answer 4

Ciliated epithelium clears mucus from lungs to mouth
Mucociliary escalator: beating of cilia to propel mucus up the airways
Mucus expelled from the lungs is swallowed or coughed up

Question 5

What is dysfunction in mucociliary clearance associated with?

Answer 5

Respiratory disease
Cystic fibrosis:
- Persistent cough
- Recurrent lung infections

Question 6

How is Cystic Fibrosis described genetically/

Answer 6

Genetic condition: faulty gene
Defect in the Cystic Fibrosis transmembrane regulator (CFTR) gene
Protein responsible for chloride transport across epithelial cell membrane

Question 7

What does Cystic fibrosis cause?

Answer 7

Causes ciliary collapse and decreased mucociliary transport
Infection + inflammation
Failure of mucusoal defence system

Question 8

What do the airway and alveolar epithelial cells participate in?

Answer 8

Inflammatory responses
Recognise and respond to foreign material
Release of inflammatory mediators to orchestrate inflammatory responses

Question 9

How does antigen presentation work in dendritic cells?

Answer 9

1. Microbe/antigen inhalation and uptake by APC
2. Microbe/antigen processing
3. Antigen presentation
4. Antigen recognition

Question 10

How does the immune system help lung defence?

Answer 10

Resident immune cells in the lungs can activate inflammatory responses
e.g. alveolar macrophages, dendritic cells