CTB6 Flashcards
What is the primary function of the airway epithelium?
To act as a protective barrier and facilitate mucociliary clearance.
What are the two main cell types in the airway epithelium?
Goblet cells (secrete mucus) and ciliated cells (move mucus).
How does mucociliary clearance protect the respiratory tract?
It removes debris, pathogens, and particulates from the airway.
What are goblet cells, and what do they secrete?
Goblet cells are epithelial cells that secrete mucins to form mucus.
What are mucins?
High-molecular-weight glycoproteins that hydrate to form mucus.
What are submucosal glands, and what is their function?
Glands in the airway submucosa that secrete mucus and antimicrobial molecules.
What is the role of ciliated cells?
Ciliated cells beat rhythmically to propel mucus towards the pharynx.
Why are ciliated cells metabolically active?
They require energy to maintain constant ciliary movement.
How does smoking affect ciliated cells?
It impairs ciliary function, reducing mucociliary clearance.
What is the basement membrane in the airway epithelium?
A thin layer of extracellular matrix supporting epithelial cells.
How does airway remodelling occur in chronic respiratory diseases?
Through fibrosis, goblet cell hyperplasia, and smooth muscle hypertrophy.
What causes goblet cell hyperplasia in asthma?
Chronic inflammation increases mucus production.
How does mucus hypersecretion affect airflow?
Excess mucus narrows airways, increasing resistance.
What is the role of tight junctions in the airway epithelium?
They maintain the barrier function by tightly linking epithelial cells.
How do cytokines influence airway epithelial cells?
Cytokines promote inflammation and upregulate mucus production.
What is the impact of oxidative stress on the airway epithelium?
It damages epithelial cells and impairs their barrier function.
What is the role of antimicrobial peptides in the airway?
They help eliminate pathogens by disrupting microbial membranes.
How does the airway epithelium respond to injury?
It undergoes repair processes involving cell migration and proliferation.
What is epithelial-mesenchymal transition (EMT)?
A process where epithelial cells gain mesenchymal properties, contributing to fibrosis.
What is the function of the respiratory basal cells?
They act as progenitor cells, regenerating damaged epithelium.
How does inflammation impact the airway epithelium?
It disrupts tight junctions, increases permeability, and promotes remodelling.
How does mucus composition change in chronic disease?
It becomes more viscous and harder to clear.
What is the role of surfactant proteins in the airway?
They reduce surface tension and play a role in innate immunity.
What mechanisms protect the airway epithelium from infection?
Mucociliary clearance, tight junctions, antimicrobial peptides, and immune cell recruitment.
What happens to airway smooth muscle in asthma?
It undergoes hypertrophy and hyperresponsiveness.
What are the main inflammatory cells in asthma?
Eosinophils, mast cells, and Th2 lymphocytes.
How do allergens trigger airway inflammation?
Allergens bind to IgE on mast cells, causing degranulation and mediator release.
How does neutrophilic inflammation differ in COPD?
Neutrophils dominate, releasing proteases that damage alveolar walls.
What role do fibroblasts play in airway remodelling?
They deposit extracellular matrix proteins, leading to fibrosis.
How does the airway epithelium sense environmental insults?
Through pattern recognition receptors (PRRs) that detect pathogens.
What are toll-like receptors (TLRs)?
PRRs that activate immune responses upon pathogen recognition.
How does hypoxia affect the airway epithelium?
It increases epithelial permeability and promotes inflammation.
What are the key features of chronic bronchitis?
Mucus hypersecretion, goblet cell hyperplasia, and chronic inflammation.
How does the airway epithelium adapt to increased pollutant exposure?
It increases mucus production and antioxidant defences but may become damaged over time.
What is the role of dendritic cells in the airway?
They capture antigens and present them to T cells to initiate adaptive immunity.
How does cigarette smoke impact airway epithelial repair?
It inhibits basal cell proliferation and repair mechanisms.
What is the significance of epithelial barrier integrity?
It prevents pathogen entry and limits inflammatory responses.
How does IL-13 contribute to airway remodelling?
IL-13 induces goblet cell hyperplasia and mucus production.
What is the role of protease inhibitors in the airway?
They prevent tissue damage by inhibiting proteases released during inflammation.
How does asthma differ from COPD in epithelial changes?
Asthma involves eosinophilic inflammation and reversible changes, while COPD involves neutrophilic inflammation and permanent damage.
What are the effects of long-term oxidative damage on the airway?
It promotes epithelial senescence, remodelling, and loss of function.
How does IL-4 influence airway inflammation?
It promotes Th2 responses, leading to IgE production and eosinophilic inflammation.
How does the airway epithelium contribute to innate immunity?
By producing antimicrobial peptides, cytokines, and chemokines.
How does mucus composition differ in cystic fibrosis?
It becomes dehydrated and thick due to defective ion transport, impairing clearance.
What is airway hyperresponsiveness?
An exaggerated bronchoconstrictor response to stimuli.
How do corticosteroids improve airway epithelial function?
They reduce inflammation, restoring barrier integrity and reducing mucus production.
What is the role of interleukin-33 (IL-33) in asthma?
It activates innate lymphoid cells, enhancing airway inflammation.
What happens during epithelial shedding in asthma?
Damaged cells detach, exposing underlying tissue and worsening inflammation.
What are the long-term effects of airway remodelling?
It leads to irreversible airflow limitation and chronic respiratory symptoms.
