Pneumocyte
From Wikipedia, the free encyclopedia
The alveoli are lined with two types of cell, the Type I and Type II pneumocytes.
Contents |
[edit] Type I
The Type I pneumocyte is a very large, thin cell stretched over a very large area. This cell cannot replicate and is susceptible to a large number of toxic insults. Type I pneumocytes are responsible for gas exchange occurring in the alveoli.
[edit] Type II
The Type II granular pneumocyte is a roughly cuboidal cell that is usually found at the alveolar septal junctions. Type II cells cover about 5% of the surface area of the alveoli, whereas type I pneumocytes (because of their squamous shape) cover 95% of the total area. Even though they cover less surface area, type II cells greatly outnumber type I cells. Type II cells are responsible for the production and secretion of surfactant.
The Type II pneumocyte can replicate in the alveoli and will replicate to replace damaged Type I pneumocytes.
[edit] See also
[edit] External links
- Dorlands/Elsevier p_25/12650572
- Histology at KUMC resp-resp17 - "Alveoli"
- Histology at BU 13905loa
- Electron micrograph at luc.edu
- Electron micrographs at buffalo.edu
 |
This cell biology article is a stub. You can help Wikipedia by expanding it. |
 |
This respiratory system article is a stub. You can help Wikipedia by expanding it. |
