Respiratory Tract Flashcards
What is the name of the epithelium that lines most of the respiratory system
Respiratory epithelium
What is sense of taste primarily
Sense of taste
What does reparatory epithelium line
Tubular portion of the respiratory system
What type of epithelium is respiratory epithelium
Pseudostratified columnar ciliated epithelium interspersed with goblet cells
What is not usually seen on H&E with light microscopy
Basement membrane of respiratory epithelium
What are the two type of epithelial cells present in respiratory epithelium
Ciliated epithelial cells
Goblet cells
What type of epithelium is the first part of the nostrils
Keratinised stratified squamous epithelium
What type of epithelium is the second part of the nostrils (where you cannot stick your finger in)
Non-keratinised stratified squamous epithelium
What is the nasal cavity lined by
Respiratory epithelium
Describe the connective tissue underneath the respiratory epithelium
Loose fibrous connective tissue contain seromucin glands and rich network of blood vessels
What do seromucin glands in the nasal cavity produce
Catarrah (snot)
What epithelium lines the roof of the nasal cavity, extending down septum and lateral wall
Olfactory epithelium
What type of epithelium is olfactory epithelium
Pseudostratified columnar ciliated epithelium
No goblet cells
No moving cilia
Contains basal cells and penetrating nerve fibres
How can you tell the difference between olfactory and respiratory epithelium
Look at the connective tissue
Olfactory has a rich network of serous glands of Bowman and large number of nerves
What do the serous glands of Bowmans secrete
Watery fluid which helps to wash the surface clean
What stain would be needed to highlight bipolar nerves on olfactory epithelium
Silver stain
Describe olfactory receptor cells
Bipolar neurons - dendrite extends to surface to become club-shaped ciliated olfactory vesicle
What is the nasopharynx lined by
Respiratory epithelium
What are the three functions of the nasal sinuses
Lower the weight of the skull
Add resonance to the voice
Humidify and warm inspired air
What is the nasal sinuses lined by
Respiratory epithelium
What is the larynx compromised of
Cartilaginous box - almost entirely hyaline cartilage
Hold larynx open in negative pressure of inspiration
What is the epiglottis formed of
Elastic cartilage
What is the larynx (expect the vocal cords) lined by
Respiratory epithelium
With loose fibro collagenous stroma with seromucous glands
What is the epithelium in the vocal cords
Thin stratified squamous epithelium overlying loose irregular fibrous tissue (Reinke’s space)
Reinke’s space - some blood vessels but almost no lymphatics
What is the tracheas supported by
Hyaline cartilage arranged in a series of c-shaped rings
What is the epithelium of the trachea
Respiratory epithelium
Seromucinous glands in submucosa
What is found at the posterior of the C-shaped cartilaginous rings in trachea
Trachealis muscle
What do
Trachea
Main bronchi
Lobar bronchi
Segmental bronchi
all contain
Smooth muscle
Partial cartilaginous rings
Respiratory epithelium
Some basal neuroendocrine cells
Seromucinous glands and goblet cells
What do bronchioles contain
Smooth muscle
Ciliated columnar epithelium
Some basal neuroendocrine cells
Few goblet cells - Clara cells
Describe clara cells
Terminal bronchioles
Cuboidal
Pale staining cytoplasm
Contain abundant mitochondria and smooth muscle
No cilia
Secretory granules
What comes after terminal bronchioles
Respiratory bronchioles
What is the first part of the distal respiratory tract
Respiratory bronchioles
What are the features of respiratory bronchioles
Cuboidal ciliated epithelium
Spirally-arranged smooth muscle
No cartilage
Describe alveoli
150-400 million/lung
250um in diameter
Gas exchange
Describe type 1 pneumocytes
40% cell population
90% of surface area
Flattened cells, flattened nucleus, few organelles
Provide part of blood air barrier
Describe type 2 pneumocytes
Cuboidal/columnar
60% of cell population
5-10 of SA
Rounded cell, round nucleus, rich in mitochondria, smooth and rough ER, spherical bodies
Produce surfactant
Describe alveolar macrophages
Luminal cells - also present in interstitium
Phagocytes particulates including dusts and bacteria
Enter lymphatics or leave via mucocillary escalator
Describe the blood air barrier
Type 1 pneumocyte on a basement membrane shared with capillary
Vascular endothelial cell
200-800nm thick
How many layers are there in the blood air barrier
Can be
3 - type 1 pneumocyte, basement membrane, vascular endothelial cell
4 - add surfactant layer
Or add cytoplasm and membrane
Describe alveoli interstitium
Where endothelial cells are not in direct contact with pneumocytes
Collagen and elastin fibres
Macrophages
Pores of Kohn
Describe pores of Kohn
Holes in alveoli walls
Help equalise pressure between adjacent alveoli
Lungs expand equally
Facilitate spread of infection
