What is a Pneumocyte type II cell?
Type II cells are spherical pneumocytes which comprise only 4% of the alveolar surface area, yet they constitute 60% of alveolar epithelial cells and 10-15% of all lung cells.
What is type II Pneumocyte hyperplasia?
In summary, prominent type 2 pneumocyte hyperplasia can occur in the settings of spontaneous pneumothorax and, similarly to other reactive processes such as squamous metaplasia, can mimic epithelial malignancy in the lung.
What is a Pneumocyte type II cell and what is its function?
The main function of type 2 pneumocytes is the production of pulmonary surfactant: Surfactant is a complex mixture of phospholipids (mainly dipalmitoyl phosphatidylcholine), carbohydrates (glycosaminoglycans) and proteins (including SP-A, SP-B, SP-C and SP-D)
What is the purpose of the substance secreted by the type II Pneumocyte?
pulmonary alveolus walls are a group called granular pneumocytes (Type II cells), which secrete surfactant, a film of fatty substances believed to contribute to the lowering of alveolar surface tension. Without this coating, the alveoli would collapse and very large forces would be required to re-expand them.
What is another name for a Pneumocyte?
Pneumocytes (or alveolar cells) are the cells that line the alveoli and comprise of the majority of the inner surface of the lungs.
What is a Pneumocyte type I cell?
Type I pneumocytes are flattened epithelial cells that cover most of the alveolar surface area and form the epithelial half of the air–blood barrier.
What is the function of type 2 pneumocytes in alveoli of lungs?
How does surfactant affect pulmonary ventilation?
The surfactant reduces surface tension within all alveoli through hydrophilic and hydrophobic forces. Insufficient pulmonary surfactant in the alveoli can contribute to atelectasis (collapse of part or all of the lung ).
What is the function of type II pneumocytes in alveoli of lungs?
What is the function of type II alveolar cells and why they are important for ventilation?
The type II alveolar cells (also known as type II pneumocytes) have two functions: (1) to repair the alveolar epithelium when squamous cells are damaged, and (2) to secrete pulmonary surfactant.
What special product is secreted by the Type II or great alveolar cells?
It is well known that AE2 cells synthesise, secrete, and recycle all components of the surfactant that regulates alveolar surface tension in mammalian lungs.
What is the difference between Type I and Type II pneumocytes?
Type II pneumocytes are larger, cuboidal cells and occur more diffusely than type I cells. They appear foamier than type I cells because of they contain phospholipid multilamellar bodies, the precursor to pulmonary surfactant. Capillaries form a plexus around each alveolus.
What is type 2 pneumocyte hyperplasia?
Type II pneumocyte hyperplasia (bronchoalveolar lavage [BAL]). In patients with acute lung injury, type II pneumocytes are markedly enlarged and may mimic adenocarcinoma, as seen here. This patient had diffuse infiltrates and marked respiratory distress resulting from diffuse alveolar damage.
How many microvilli are present in Type II pneumocytes?
Rarely, small groups of two or three type II pneumocytes can be observed. On their surface, they characteristically contain many microvilli (Fig. 8.33). The cytoplasm is rich in organelles.
What organelles are found in Type II pneumocytes?
Rarely, small groups of two or three type II pneumocytes can be observed. On their surface, they characteristically contain many microvilli (Fig. 8.33). The cytoplasm is rich in organelles. Rough endoplasmic reticulum, free ribosomes, mitochondria, lysosomes, multivesicular bodies, and a prominent Golgi apparatus can be found.
