Histology Flashcards
What is progression through the airway marked by
- Decrease in height of epithelial cells
- Decrease in cartilage
- Decrease in glands (unicellular and multicellular)
- Increase in relative amount of SM
- Increase in relative amount of elastic fibres
What part of the airways is covered by stratified squamous epithelium
Oropharynx
Epiglottis
Vocal folds
What is metaplasia
Conversion to stratified squamous in areas where abrasion occurs
Increase in goblet cells, decrease in ciliated cells in smokers and city dwellers
Difference in epithelium between lower and upper respiratory tract
Ciliated cells predominate to the level of the respiratory bronchiole, initially tall columnar, becoming low columnar to cuboidal
- ciliary escalator
What cells are sensory receptor cells
Brush cells
What cells make up the stem cell poulation
Basal cells
Name the cells of the diffuse neuroendocrine system (DNS)
Small granule cells
What do the mucous goblet cells do
Secrete mucous
Found in abundance in the upper airway, decreasing in the bronchi, absent at terminal bronchiole
Epithelium of bronchioles
Ciliated pseudostratified columnar epthelium decreasing to ciliated simple cuboidal in terminal bronchioles
Cells of terminal bronchioles
Clara cells which secrete a protective glycoprotein substance
What are bronchioles the anatomical site of
Asthma due to the relative abundance of SM in the lamina propria
Type I pneumocytes of the alveoli
- 90% of alveolar SA but only 40% of cell population
- Thin squamous cells, highly attenuated cytoplasm joined by tight junctions
Type II pneumocytes of the alveoli
- 10% of alveolar SA, 60% of cell population
- Approx cuboidal in shape
- Joined to Type I by tight junctions and desmosomes
- Stem cell population giving rise to both Type I and II
- Secretes SURFACTANT
