Histopathology of lung disease

Question 1

Characteristics of trachea and bronchi

Answer 1

Pseudostratified ciliated columnar epithelial cells
Height decreases as you look distally 
Goblet cells 
Basal cells 
Lamina propria 
Submucosa secretes mucus 
C shaped hyaline cartilage ring

Question 2

What do goblet cells do?

Answer 2

Secrete mucus

Question 3

What do basal cells do?

Answer 3

Attach to basal lamina

Question 4

Characteristics of bronchioles

Answer 4

Height of epithelial cells decreases - near simple cuboidal epithelium
No cartilage or submucosal glands
Smooth muscle to support

Question 5

Characteristics of terminal bronchioles

Answer 5

Ciliated cuboidal epithelia

Contain club cells

Question 6

What do club cells do?

Answer 6

Secrete surfactant

Question 7

Characteristics of respiratory bronchioles

Answer 7

Simple squamous epithelium

May contain alveoli

Question 8

Characteristics of alveolar ducts/alveoli

Answer 8

Gas exchange
Mainly type I alveolar cells
Macrophages

Question 9

What does fat look like on slide?

Answer 9

White spaces

Question 10

What are dust cells?

Answer 10

Macrophages in lung

Question 11

What do type 2 alveolar cells look like?

Answer 11

They protrude into space

Question 12

Asthma

Answer 12

• IgE hypersensitivity response
• Acute asthma is reversible
• Chronic asthma: thickening of bronchial walls, hypertrophy and hyperplasia of smooth muscle, immune infiltration by eosinophils, mucus lining bronchial lumen is thicker and contains immune cells - eosinophils

Question 13

Bronchiectasis

Answer 13

• Lower lobes
• Caused by persistant bacterial infection of bronchi or blockage of bronchi by foreign bodies or tumours
• Irreversible airway dilation, thickening of walls, chronic infection of walls
• Destruction of normal elastic fibres and muscle in bronchus wall, tissue replaced by fibrous tissue, thickening of wall results in weaker structure
• Wall dilates but mucous secretions not moved as efficiently = increase in bacterial infections

Question 14

Chronic bronchitis

Answer 14

• Persistent cough for three consecutive months for at least two consecutive years

Caused by:

• 1) smoking or pollution irritating the bronchial mucosa
• 2) chronic infection e.g. acute bronchitis
• Changes are variable.
• Hyperplastic changes result in a thicker bronchial wall.
• Chronic inflammatory cells in the submucosa - macrophages, neutrophils and lymphocytes hypertrophyof mucosal smooth muscle hyperplasiaof mucinous glands in trachea and bronchi results in more mucous production
• Hyperplasiaof the epithelial cells and loss of cilia
• Increase in number ofgoblet cellsin the epithelium of the lower bronchi and bronchioles

Question 15

Emphysema

Answer 15

• Centriacinar emphysema: most common, affects alveoli of respiratory bronchiuole, seen in upper lobe of lung, common in cigarette smokers
• Panacinar emphysema: from respiratory bronchiole to terminal alveoli, more common in lower lungs, alpha1 anti-trypsin deficiency
• Permanent enlargement of airspaces distal to terminal bronchioles - destruction of alveolar walls, no fibrosis, may lead to pneumothorax

Question 16

Bronchopneumonia

Answer 16

• Specific areas of lung rather than whole lobes
• Areas are infiltrated with inflammatory cells - around bronchi
• Resolves around antibiotic treatment
• Lots of immune cells

Question 17

Fungal infections

Answer 17

• Candida albicans - normal floral of oral, GIT and vagina
• Can occur in immunocompromised individuals
• Infections from yeast
• Progress to necrotising pneumonia
• Asthmatic patients may develop hypersensitivity to fungus