Structure and function of the airways Flashcards
Why does the trachea not have rings of cartilage?
There is the oesophagus running down the back of the trachea
So if rings went all the way around- they would impact swallowing food down the oesophagus
What is the shape of the cartilage in the trachea?
C shaped
What are the “basic” aspects of the airway?
airways, lungs, nasal passages
Go from the trachea down, what are the airways?
Trachea, primary bronchus, secondary bronchus (lobar), tertiary bronchus (segmental), bronchioles, alveolus
What provides mechanical stability to the airways?
cartilage (holds them open)
what type of branching does the airway have?
dichotomous branching
What happens at the alveolar region?
gas exchange
What are the components of the alveolar region?
Alveolar duct, alveoli, alveolar sac, respiratory bronchioles, terminal bronchiole (non-cartilaginous)
Where specifically in the alveolar region does gas exchange occur?
alveolar unit- capillary endothelium
What are the cells present in the pipework of the alveolar unit?
Type I cell, Type II cell, Macrophage, stromal cell (fibroblast)
What are type I cells?
very thin, delicate barrier (facilitate gas exchange)
What are Type II cells?
replicate to replace Type I, secrete surfactant and antiproteases
Part of xenobiotic metabolism
What is the role of surfactant in the lungs?
reduces surface tension
What is xenobiotic metabolism?
getting rid of bad stuff that has been inhaled in simple terms
The xenobiotic metabolism in the lung, an organ of first entry of xenobiotics into the organism, is crucial for inhaled compounds entering this organ intentionally (e.g. drugs) and unintentionally (e.g. workplace and environmental compounds).
How much do type I cells cover?
over 95% of alveolar surface
Are there more Type I or Type II cells?
more type II
What are 2 basic functions of the respiratory airways?
getting air efficiently to the gas exchange region, and keeping the pipework clear.
What are the conduits (pipes) for?
conduct O2 to alveoli, conduct CO2 out of the lungs
- for gas exchange
What are the conduits (pipes) facilitated by?
mechanical stability (cartilage)
control of calibre (smooth muscle)
protection and cleansing
What are the regions of the pharynx?
nasopharynx
Oropharynx
Laryngopharynx
What are the conchae in the nasal passage?
high vascularised- contribute to warming and humidification of intra-nasally-inhaled air
What do nasal hairs do?
they filter out large particles
What is the pharynx?
a common passage for food, liquids, and air
What is the organisation of airway structures (transverse section)?
What is the structure of the airway wall?
mucus layer–> cilia–> epithelial cells
What are the lining cells?
ciliated, intermediate, nursh, basal
What are the contractile cells?
smooth muscle (airway, vasculature)
What are the secretory cells?
goblet (epithelium), mucous, serous (glands)
What are the connective tissue cell types?
fibroblasts, interstitial cell (elastin, collagen, cartilage)
What are the neuroendocrine cell types?
Nerves, ganglia, neuroendocrine cells, neuroepithelial bodies
What are the vascular cells?
endothelial, pericyte, plasma cells (+smooth muscle)
What are the immune cells?
Mast cell, dendritic cell, lymphocyte, eosinophil, macrophage, neutrophil