Histology Flashcards
What specialised epithelium is present in the roof of the nasal cavity?
Olfactory epithelium
Which processes are carried out on inspired air in the nasal cavity?
Warming
Moistening
Filtering
What sort of epithelium lines the vestibule (the first part of the nasal cavity)?
keratinised stratified squamous epithelium
Describe respiratory epithelium.
Psuedostratified ciliated columnar epithelium with goblet cells.
Describe the lamina propria in the nasal cavity.
It is underneath the respiratory epithelium. It is a band of connective tissue containing seromucous glands and a rich venous plexus.
What happens when the nose becomes “blocked”?
The venous plexus in the lamina propria becomes engorged with blood in response to some mediator e.g. histamine.
What type of epithelium lines the oropharynx, anterior surface and upper part of the posterior surface of the epiglottis?
Non-keratinised stratified squamous epithelium
Describe the epithelium which lines the larynx.
It is lined by respiratory epithelium (i.e. pseudostratified ciliated columnar epithelium with goblet cells) apart from the vocal cords and adjacent structures which are lined with stratified squamous epithelium.
Describe the cartilage in the trachea.
15-20 C shaped hyaline cartilage rings.
The open end points towards the oesophagus and is lined by fibroelastic tissue and smooth muscle.
Describe the cartilage in the bronchi.
Irregularly shaped cartilage plates. They are initially quite extensive but become more sparse as you move further down the respiratory tree.
What is the bronchus called when it has lost its cartilage?
A bronchiole.
Describe the structure of the bronchioles.
less than 1mm in diameter.
Lack cartilage and glands but may contain a few goblet cells in their initial portion.
As you progress down the respiratory tree to the smallest bronchioles the epithelial cells decrease in height from columnar to cuboidal.
The lamina propria consists of smooth muscle and elastic and collagenous fibres.
a) What is the name of the non-ciliated cells in the terminal bronchioles that project above the level of the adjacent ciliated cells?
b) What shape are these?
c) What is their function?
a) Clara cells
b) Dome-shaped cells
c) Stem cells
Detoxification
Immune modulation
Surfactant production
Describe the lining of the alveoli.
Discontinuous simple squamous type 1 alveolar cells cover 90% of the surface of the epithelial lining.
Type 2 cells are polygonal in shape, they are usually found in the corners and produce surfactant. They are covered in microvilli.
Where are alveolar macrophages found and what do they do?
They are free cells- either in the septa or migrating over the luminal surfaces of the alveoli.
They phagocytose inhaled particles that may have escaped entrapment by mucous in the airway.
They will typically migrate up the bronchial tree facilitated by the mucociliary network and be swallowed.
