73 - Respiratory Histology Flashcards
Effect of tubinate bones
Increase surface area of nasopharynx
Location of epiglottis
Where larynx and oesophagus diverge
Structure immediately below epiglottis
Larynx
Function of the larynx
Phonation
Cells lining airways 1 2 3 4
1) Pseudostratified epithelium. 2) Ciliated cells. 3) Secretory cells (goblet cells, specialised glands) 4) Sensory cells to initiate coughing to expel irritants
Cells in this slide
1) Ciliated columnar cells (30%) 2) Goblet cells (30%) 3) Basal (stem) cells (30%) 4) Serous cells (3%) 5) Brush cells with microvili (3%) 6) Small granule cells (3%)
Function of ciliated columnar cells
Move mucus. Move mucus upwards through the airways into the oesophagus. Mucociliary elevator.
Function of basal (stem) cells
In the base of the epithelium, renew the epithelium
Function of brush cells
Not clear. Maybe sensory
Function of serous cells
Unknown
Function of small endocrine cells
Endocrine
Aetiology of smoker’s cough
Smoking kills airway cilia, which can no longer operate mucociliary elevator. Coughing is only way to clear airways.
Trachea dimensions
12cm long, 2cm diameter
Trachea structure
10 - 12 rings of hyaline cartilage. C-shaped cartilage, opening backwards, bounded by smooth muscle.
Layers of trachea
Mucosa, submucosa, adventitia
Why does the trachea need to be stiff?
To resist the negative pressure that can arise in the conducting airways
Function of trachea smooth muscle
Can alter the diameter of the trachea
C= C-shaped cartilage M = Mucosa S = Submucosa A = Adventitia
Parts of the tracheal mucosa
Respiratory epithelium and lamina propria
Which part of the trachea are the cartilage rings considered to be?
Adventitia?
What does the trachea split into?
Two primary, extrapulmonary bronchi in the thorax
What do primary bronchi split into?
Each split into five branches (three right, two left)
Number of branches of the airways
~23
Structure of a bronchus 1 2 3 4 5
1) Initially like trachea, but with thinner walls 2) Cartilage ring becomes cartilage plates in intrapulmonary bronchi. 3) Smooth muscle is at boundary between the lamina propria and submucosa. 4) Glands present 5) Lymphoid nodules present
C = Cartilage plate reinforcing wall G = Glands S = Smooth muscle (G and S arranged circumferentially, parts of the submucosa)
Difference between bronchi and bronchioles
Bronchioles have lost cartilage