Respiratory epithelium

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

Phloston

Osaka, Japan
Removed
Lifetime Donor
10+ Year Member
Joined
Jan 18, 2012
Messages
3,882
Reaction score
1,675
Could someone please just help me with the different types of respiratory epithelium at different locations? FA doesn't get too specific about it.

I've inserted my general guesses below. I had the impression that the epithelium slowly becomes more cuboidal and increasingly less ciliated as we move inferiorly, but I'm just not sure as to where the actual changes occur. Please help me fill in the blanks.........

------


Type of epithelium

Vestibule of nasal cavity: stratified squamous (with hair)

Turbinates of nasal cavity: ciliated pseudostratified columnar, goblet cells

Nasopharynx: ciliated pseudostratified columnar, goblet cells

Oropharynx: stratified squamous?

Laryngopharynx: ciliated pseudostratified columnar, goblet cells

Larynx (ventricular folds [false vocal cords]): ciliated pseudostratified columnar

Larynx (vocal folds [true vocal cords]): stratified squamous

Trachea: ciliated pseudostratified columnar, bronchial cells of Kulchitsky, goblet cells, brush cells (sensory), basal cells (cell reserve)

Bronchi: ciliated pseudostratified columnar, goblet cells

Terminal bronchioles: Clara cells (non-ciliated columnar), mixed ciliated pseudostratified columnar? / cuboidal?, fewer goblet cells

Respiratory bronchioles: simple squamous, mixed cuboidal?

Alveolar ducts / aveoli: simple squamous (type-I), cuboidal (type-II)


???

Members don't see this ad.
 
Last edited:
I had the impression that the epithelium slowly becomes more cuboidal and increasingly less ciliated as we move inferiorly

That summary is pretty accurate, the way I remember it. Although I don't have resources at hand, here is a tidbit from my portable notes:

Vestibule of nasal cavity is covered by stratified squamous epithelium with hair. Posterior to this, the respiratory component of nasal cavity including the turbinates are lined by respiratory epithelium (pseudostratified columnar ciliated epithelium with goblet cells). The nasopharynx is lined by same.
In the larynx, vocal folds (true vocal cords), covered by stratified squamous epithelium and containing in them the vocalis muscle, control the pitch. The ventricular folds (false vocal cods) sitting above them have no muscle but contribute to resonance; they are lined by respiratory epithelium. The trachea is 10 cm x 2.5 cm, its mucosa composed of respiratory epithelium, goblet cells, brush cells (sensory), small granule cells (enteroendocrine), and basal cells (cell reserve). The mucosa rests on a thick basement membrane. The lamina propria and submucosa are very saturated with lymphatic tissue. The tracheal cartilages are C-shaped and partially calcified in older people. The adventitia binds trachea to mediastinum.
Upon division, mainstem bronchi split into lobar bronchi (2 left, 3 right), and then segmental bronchi (8 left, 10 right); as each segment has its own bronchus, blood supply and septa, they are good units for surgical resection. The bronchi are initially similar to trachea (except cartilage is in rings); as they enter the lungs, cartilage rings changed to plates, and the bronchial smooth muscle forms a circular layer.
Once the plates disappear, the branch is designated a bronchiole (< 1 mm). The epithelium changes to simple columnar and then to simple cuboidal. Goblet cells decease in number. The terminal bronchioles are lined with Clara cells, which secrete a lipoprotein, which prevents airway collapse. The conducting portion ends with terminal bronchioles, and the respiratory portion is respiratory bronchioles, alveolar ducts, sacs, and alveoli themselves. In alveoli, surface area coverage is 95% type I, and 5% type II, which secretes surfactant of four kinds (A-D).
 
Thanks a lot! Based on what you've written above, I've modified the list.

However, there are still parts that need tweaking. Does anyone have anymore input??

Memorizing this list seems pretty low-yield to me. Just try and think about it conceptually...i.e. how does it change as you go along the tract and why? And how this might relate clinically. The rest of the details seem overkill to me. Example: I seriously doubt you'll have a question asking about whether or not Clara cells are ciliated. There's just a lot more clinically relevant ways to test this information than small details like that.
 
Last edited:
Members don't see this ad :)
Memorizing this list seems pretty low-yield to me. Just try and think about it conceptually...i.e. how does it change as you go along the tract and why? And how this might relate clinically. The rest of the details seem overkill to me. Example: I seriously doubt you'll have a question asking about whether or not Clara cells are ciliated. There's just a lot more clinically relevant ways to test this information than small details like that.

:thumbup::thumbup: Pretty much what I thought when I read this.
 
Memorizing this list seems pretty low-yield to me. Just try and think about it conceptually...i.e. how does it change as you go along the tract and why? And how this might relate clinically. The rest of the details seem overkill to me. Example: I seriously doubt you'll have a question asking about whether or not Clara cells are ciliated. There's just a lot more clinically relevant ways to test this information than small details like that.

Don't act like you're surprised. We're all over-achievers. :)
 
Memorizing this list seems pretty low-yield to me. Just try and think about it conceptually...i.e. how does it change as you go along the tract and why? And how this might relate clinically. The rest of the details seem overkill to me. Example: I seriously doubt you'll have a question asking about whether or not Clara cells are ciliated. There's just a lot more clinically relevant ways to test this information than small details like that.

srsly this...:thumbup:
 
Memorizing this list seems pretty low-yield to me. Just try and think about it conceptually...i.e. how does it change as you go along the tract and why? And how this might relate clinically. The rest of the details seem overkill to me. Example: I seriously doubt you'll have a question asking about whether or not Clara cells are ciliated. There's just a lot more clinically relevant ways to test this information than small details like that.

My professor calls them "Casper the Ghost" cells.

He's 70.

Clara_cell_mouse_lung_485311_copy.jpg
 
Top