5 Structure and Function of the Airways Flashcards
(40 cards)
Q: Which interface is designed for gas exchange? What else does this interface need to be able to do? why?
A: Interface between external air and alveolar region for gas exchange
other substances breathed in as well -> must be equipped to defend itself
Q: What the 2 main functions of the airways? What facilitates these functions? (3) Describe. (3,2,2)
A: conduit to conduct O2 to alveoli; conduct CO2 out of lung = gas exchange
facilitated by
- mechanical stability : cartilage -> keeps open
- cartilage is C-shaped with opening at back of trachea for oesophagus (C shaped so doesn’t make it difficult for food to go down) -> allows for bronchoconstriction
- cartilage is slightly offset compared to each other -> ++ tensile strength)= less easily compressed - control of calibre (smooth muscle)
- protection and “cleansing”
Q: Name 7 cell categories.
A: Lining cells
Contractile cells
Secretory cells
Connective tissue
neuroendocrine
Vascular cells
Immune cells
Q: Name the 4 lining cells.
A: Ciliated, intermediate, brush, basal
Q: What are contractile cells called? (2)
A: Smooth muscle (airway, vasculature)
Q: Name 3 secretory cells. Include 2 locations.
A: Goblet (resp epithelium and reproductive tracts- are cells in their own right), mucous (specialised epithelium cells), serous (glands)
Q: Name 2 connective tissue cells. 3 examples?
A: Fibroblast, interstitial cell (elastin, collagen, cartilage)
Q: Name 4 neuroendocrine cells.
A: Nerves, ganglia, neuroendocrine cells, neuroepithelial bodies
Q: Name 3 (+1) vascular cells.
A: Endothelial, pericyte, plasma cell (+ smooth muscle)
Q: Name 6 immune cells.
A: Mast cell, dendritic cell, lymphocyte, eosinophil, macrophage, neutrophil
Q: What mixture lines airway epithelium? What does it contain? (9) Produced by?
A: Mucus- mucins, water, electrolytes, plasma, mediators, inorganic salts, antiseptic enzymes (such as lysozymes), immunoglobulins, glycoproteins such as lactoferrin and mucins
goblet cells
Q: In airway epithelium, what moves mucus along? process name? What does airway epithelium act as? What are the 2 main cells of airway epithelium?
A: movement of mucous by cilia -> mucociliary clearance
physical barrier
- ciliated
- goblet
Q: What is produced by airway epithelium? (2) Name 6 examples, including what produces it for some.
A: production of regulatory and inflammatory mediators
- NO by NOS
- CO by hemeoxygenase
- Arachidonic acid metabolites e.g. prostaglandin
- Chemokines e.g. ILs
- Cytokines e.g. GM-CSF
- Proteases
Q: What do ciliated cells contain? What are cilia? structure? role? What lies on top of cilia?
A: ++ mitochondria
cilia: have apical “hooks” (engage with mucus); 9+2
metacronal beating to move mucous to back of throat with particles etc.
mucous layer on top of cilia
Q: What do goblet cells contain lots of? What happens to this structure? (2) What is the structure of this structure outside of the goblet cell?
A: mucin granules in highly condensed form
hydrates when fuses with cell membrane -> expelled
when they are released- increase in size by 600 (many 100) fold (take in water)
Q: What is also part of airway epithelium? where? (3) What do these structures contain and what do they do? (3)
A: Airway submucosal glands
- between 2 epithelial (or goblet) cells
- extend down past basal lamina
- > basal part embedded in smooth muscle layer
- mucous cells secrete mucous
- serous cells secrete antibacterials (e.g. lysozyme)/
- glands also secrete water and salts (e.g. Na+ and Cl-)
Q: What do smooth muscle cells provide (functions) in human airways? (3) What do they secrete? (3) how much?
A: -Structure
- Tone (airway calibre): contraction; relaxation
- Secretion: mediators; cytokines; chemokines (little) -
Q: What can inflammation of smooth muscle cells in airways cause? Example? Explain (3)
A: contributes to disease process
asthma ->
hypertrophy -> impact on calibre of lumen + upregulates production of mediators
Q: What percentage of cardiac output goes to airway vasculature? What circulation is this? What is the rate of blood flow to airway mucosa (mucous membrane)? How does this compare to other tissues?
A: 1-5%
trachea-bronchial circulation
100-150ml/min/100g tissue (amongst highest to any tissue) = lots of input
Q: Where do bronchial arteries arise from? (3) What are the 2 types of airway vasculature circulations? Where does blood return to for each one? (1,2)
A: bronchial arteries arise from many sites on: aorta, intercostal arteries and others
- blood returns from tracheal circulation via systemic veins
- blood returns from bronchial circulation to both sides of heart via bronchial and pulmonary veins
Q: What does the subepithelial microvascular network have? Functions? (6)
A: -good gas exchange
- contributes to warming of inspired air
- contributes to humidification of inspired air
- clears inflammatory mediators
- clears inhaled drugs
- supplies airway tissue and lumen with inflammatory cells
- supplies airway tissue and lumen with proteinaceous plasma (plasma exudation)
Q: What is plasma exudation in terms of airways? How does it occur? (4)
A: the supply of airway tissue and lumen with proteinaceous plasma
post-capillary venular endothelial cells contract with different stimuli -> pull away from each other -> plasma leaks out through gap -> tissue
Q: What controls plasma exudation in airways? (2-1,2)
A: sensory nerves (despite motor function)
inflammatory mediators (histamine, platelet activating factor)
Q: How is airway function controlled? (4) Describe each. (2,4,2,2)
A: nerves: parasympathetic (cholinergic); sensory
- regulatory and inflammatory mediators: histamine; arachidonic acid metabolites (e.g. prostaglandins, leukotrienes); cytokines; chemokines
- proteinases (e.g. neutrophil elastase)
- reactive gas species (e.g. O2-, NO)