Lecture 25 Flashcards
What does injury to the ciliated bronchial epithelium result in
Degeneration, detachment and exfoliation
What does injury to the ciliated bronchial epithelium follows with
- Inflammation, cell proliferation, cell differentiation and repair
What is the exudate like with injury to the bronchi
- Fibrinous, catarrhal, purulent, fibronecrotci
- Chronic inflammation - also goblet cell hyperplasia and excess mucus production
Explain the chronic injury to the bronchi
Can lead to squamous metaplasia of bronchial epithelium -> breakdown of mucociliary clearance
Goblet cell hyperplasia -> chronic catarhal inflammation
What can chronic bronchitis lead to
- Bronchiectasis
- Pathological and permanent dilation of the bronchus from accumulation of exudates
- Partial destruction of the bronchial wall
- Due to proteolytic enzymes and free radicles from neutrophils and macrophages
Severe Bronchiectasis
Why is the epithelium susceptible to injuty
- High vulnerability to oxidants and free radicles
- Presence of club cells righin antioxidants which generate toxic metabolites
- Alevolar macropages and leukocytes accumulate
What is bronchiolitis
- Classified as necrotizing, suppurative, catarrhal of granulomatous
- In severe injury, the exudate becomes infiltrated with fibroblast and forms microscopic polyps inside the bronchiolar lumen
- May block air flow
What are the chronic injury to bronchioles
- Peribronchiolar lymphoid hyperplasia
- Mild persistent injury
- Goblet cells proliferate and change the properties f bronchiolar secretions
- Goblet cell metaplasia
- Mucous needs to be cleared by coughing
- As there is partial or coplete blockage of the lumen of bronchioles by mucus hypersecretion
- Goblet cells proliferate and change the properties f bronchiolar secretions
- Pulmonary emphysema and atelectasis occur
- CHaracteristically seen in chronic obstructive pulmoary disease
- Recurrent airway obstruction = heaves in horses
What is reccurent airway obstruction in horses
- Haves
- Signs
- Recurrent respiratory distress
- Chronic cough
- Poor atletic performance
- Airway neutrophilia and mucous hypersecretion
What is hypothesis of RAO
Dust paticles upregulate production of cytokines by alveolar macrophages which attracts neutrophils
- Neutrophils induce bronchiolar damage
- Goblet metaplasia
- Preibronchial accumulation of lymphocytes and esinophils and interstitial fibrosis
- Peribronchial fibrosis and epithelial cell hyperplasia are inconsistent findings
- Alveolar emphysema may be present
Goblet cell metaplasia
Alcian blue stain to show mucus
ROA - emphysema
ROA - mucous and exudate in airway
RAO - mucous and exudate in airways
What is feline asthma
- Feline allergic bronchitis/bronchiolitis
- Reccurent bronchoconstriction, coughing or dyspnoea
- Poorly understood
Describe Type I pneumocytes
- Very susceptibleto aerogenousand haematogenous injury -> swelling and vacuolation
- Repair is possible as long as the basement membrane is intact
- Cuboidal pneumocytesproliferate
Describe type Ipneumocytes
- Line the denuded alveolar basement membrane and differentiate into Type I pneumocytes
- In diffuse injury, the proliferating Type II pneumonocytes give the appearance of glandualar structure called - epithelialisation
Pulonary epithelialialisation: proliferating Type II pneumonocytes
What injury to the alveoli
- Loss of type I pneumocytes
- Means damage to blood-air barrier and alveolar capillaries leak plasma
- Alveolar macrophages remove fluid and cellular debris
- If injury is persistent, fibroblasts proliferate leading to intra-alveolar fibrosos
- Extensive alveolar fibrosis seen in toxic and allergic pulmonary disease
- Fibrosis has a major effect on lung function
What is the most important leukocyte in lung inflammation
Alveolar macrophages
- Rapid recruitment and migration of leukocytes into alveoli
- Alveolar fulid contains large amounts of inflammatory mediators
- Large capillary network
- Neutrophils recruited into alveolar spaces within minutes of local and systemic inflammatory response
What is pulmonary oedema
- Protein leakage from flasma into alveoli and formation of fibrin can be rapid
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What is the formation of ‘hyaline membranes’
- Plasma proteins mixed with necrotic Type I pneumonocytes and pulmonary surfactant can form eosinophilic membranes along alveolar septa
Hyaline membranes - cows lung
