Structure and function of the airways Flashcards
(47 cards)
What is the branching the airways?
dichotomous branching
Where does the mechanical stability come from?
cartilage
What are type 1 cells in the alveolar regions?
- incredibly thin (like fried eggs) -cover ~95% of alveolar surface
- delicate barrier
- Facilitate gas exchange
What are type II cells?
- Replicate to replace type 1 ells
- release surfactant (reduces surface tension), antiproteases
- Xenobiotic metabolism
- Type II cells – greater numbers than Type I cells, but only cover ~5% of surface
What is the basic function of the respiratory airways?
Getting air efficiently to the gas exchange region. Keeping the pipework clear
What are the airways conduit to?
Conduit (‘pipes’) to:
- conduct O2 to the alveoli
- conduct CO2 out of the lung
- gas exchange
What are the airways facilitated by?
Facilitated by:
- mechanical stability (cartilage)
- control of calibre (smooth muscle)
- protection and ‘cleansing’
What does the pharynx do?
a common passageway for food, liquids and air.
What do the conchae do?
highly vascular – contribute to warming and ‘humidification’ of intra-nasally-inhaled air
What do the nasal hairs do?
Nasal hairs filter out large particles
What cell type are lining cells in the airway?
- Ciliated
- Intermediate
- Brush
- Basal
What cell type are contractile cells in the airway?
-Smooth muscle (airway, vasculature)
What cell type are secretory cells in the airway?
- Goblet (epithelium)
- mucous
- serous (glands)
What cell type are connective tissue in the airway?
-Fibroblast
-interstitial cell
(elastin, collagen, cartilage)
What cell type are neuroendocrine cells in the airway?
- Nerves
- Ganglia
- Neuroendocrine cells
- Neuroepithelial bodies
What cell type are vascular cells in the airway?
- Endothelial
- Pericyte
- Plasma cell (+smooth muscle)
What cell type are immune cells in the airway?
- Mast cell
- Dentritic cell
- Lymphocyte
- Eosinphil
- Macrophage
- Neutrophil
How is mucin secreted?
Mucin secretion by guinea pig tracheal goblet cell
expansion of intra-granular mucin upon secretion; to ATP, Real Time
What are the airway submucosal glands?
- Mucous cells secrete mucus
- Serous cells secrete anti-bacterial enzymes (e.g. lysozyme)
- Glands also secrete water and salts (e.g. Na+ and Cl-)
What is the function of airway epithelium?
- Secretion of mucins, water and electrolytes
- components of ‘mucus’ (+ plasma, mediators etc)
- Movement of mucus by cilia – mucociliary clearance
- Physical barrier
What is produced by airway epithelium?
-Production of regulatory and inflammatory mediators:
1. Nitric oxide (NO - via nitric oxide synthase, NOS)
2. Carbon monoxide (CO - via hemeoxygenase, HO)
3. Arachidonic acid metabolites (e.g. prostaglandins – via COX)
Chemokines (e.g. interleukin (IL)-8)
4. Cytokines (e.g. GM-CSF)
5. Proteases
How is NOS in airways?
- NOS expression in human airway epithelium
- Brown staining = nitric pride synthase (NOS) - produces nitric oxide (NO)
How does airway smooth muscle function in inflammation?
- Structure:
- Hypertrophy
- Proliferation - Tone: airway caliber (with or without inflammation)
- Contraction
- Relaxation - Secretion: (with or without inflammation but increase if inflammation)
- Mediators
- Cytokines
- Chemokines
What are the secretory functions in airway smooth muscle with Inflammation or exposure to bacterial products or cytokines?
-Activates NOS -> NO
-Activates COX -> Prostaglandins
-Increase prod Cytokines
-Increase prod Chemokines
-Increase prod adhesion molecules
>Last three used in inflammatory cell recruitment