Airways Flashcards
(21 cards)
What is the pathway of air in the airways?
- Trachea
- Primary bronchi
- Secondary bronchi
- Tertiary bronchi
- Bronchioles
- Alveoli
What is dichotomous branching?
One tube branches into 2
- trachea —> 2 primary
bronchi
- primary bronchus —> 2
secondary bronchi
Which parts of the respiratory system are cartilaginous?
Cartilaginous:
- Trachea —> C-shaped rings (keeps oesophagus
unimpeded)
- Bronchi
Non-cartilaginous:
- Bronchioles
- Alveoli
Which 4 cell types make up an alveolus?
- Type I
- Type II
- Macrophage —> immunity
- Stromal —> produce matrix (fibroblasts)
What is the function of type I alveolar cells?
Allow for gas exchange
- thin, delicate barrier
- make up 95% of lining (even though there are less in
number)
What are the 3 functions of type II alveolar cells?
- Replicate —> replace type I
- Secrete surfactant and anti-proteases
- Xenobiotic metabolism
- make up 5% of lining (even though there are more in
number)
Which 3 processes facilitate gas exchange in the airways?
- Mechanical stability —> cartilage
- Control of calibre —> smooth muscle
- Protection and cleansing
What are the 3 adaptations of the nasal passage?
- Nasal conchae - highly vascular
—> warm and humidify air - Hairs —> filter large particle
- Pharynx —> connection to mouth
What is the structural organisation of airways? (7)
- Cartilage —> outermost
- Smooth muscle
- Blood vessels
- Ciliated cells
- Goblet cells
- Submucosal glands
- Mucus
How are airways kept clean?
Goblet cells secrete mucin granules —> particles stick to mucus layer —> wafted out by cilia
What are the 7 cell types of airways?
- Lining cells
- Contractile cells
- Secretory cells
- Connective tissue
- Neuroendocrine
- Vascular cells
- Immune cells
What do submucosal glands secrete?
- Mucous acini —> mucus
- Serous acini —> anti-bacterial enzymes
- Water
- Salt
What is the structure of cilia?
- Anchoring intracellular proteins —> connect to
epithelial cells - Axoneme —> microtubule
- Apical hooks —> hook to mucus
- 9 cilia around 2 goblet cells
- 200 cilia per cell
What are the 4 functions of airway epithelium?
- Secrete mucus components (mucins, water,
electrolytes) - Mucociliary clearance
- Physical barrier
- Regulatory and inflammatory mediator production
- NO, CO, arachidonic acid metabolites,
chemokines, cytokines, proteases
- NO, CO, arachidonic acid metabolites,
What are the 3 functions of airway smooth muscle?
- Structure
- Tone —> contract/relax
- Secretion —> mediators, cytokines, chemokines
How does tracheo-bronchial circulation work?
In:
- Bronchial arteries branch from aorta, intercostal arteries etc.
- 100-150 ml/min/100g tissue (v high)
- only 5-10% cardiac output
Around:
- Subepithelium microvasculature
Out:
- Trachea —> systemic veins
- Bronchi —> bronchial veins
—> pulmonary veins
What are the 7 functions of tracheo-bronchial circulation?
- Direct gas exchange
- Warms and humidifies inspired air
- Clears inflammatory mediators and inhaled drugs
- Inflammatory cell supply
- Plasma exudation
What are airway functions controlled by? (4)
- Nerves
- parasympathetic
- sympathetic
- sensory
- Regulatory and inflammatory mediators
- histamine
- arachidonic acid metabolites
(prostaglandins/leukotrienes) - cytokines
- chemokines
- Proteases
- Reactive gas species
What is the pathway of airway innervation?
Sensory neurones:
- to spinal cord —> dorsal root ganglion c
—> cervical thoracic ganglion eg. NO r
- to brain stem —> nodose ganglion c
Parasympathetic neurones:
- to smooth muscle —> parasympathetic (ACh) c
Hormonal:
- to smooth muscle —> adrenaline c
Which regulatory-inflammatory cells are in airways?
- Eosinophils
- Neutrophils
- Macrophages
- Mast cells
- T lymphocytes
- Structural cells
What are 3 common respiratory diseases?
- Asthma —> 5% population
- COPD —> 4th cause of death
- CF
- obstructive —> inflammation
