What cells secrete surfactant?
Pulmonary surfactant is produced by alveolar type II cells and is required for lung function after birth. Pulmonary surfactant is composed of lipids and four lipid-associated proteins, SP-A, SPB, SP-C, and SP-D, that regulate surfactant function, structure, metabolism, and innate host defense.
Do type 1 cells secrete surfactant?
Type 1 epithelial cells cover the greatest area of the alveolar surface, while type 2 cells function to synthesize and secrete surfactant material in the form of lamellar bodies and also secrete other proteins.
What are type 1 and type 2 cells?
The type I cell is a complex branched cell with multiple cytoplasmic plates that are greatly attenuated and relatively devoid of organelles; these plates represent the gas exchange surface in the alveolus. On the other hand, the type II cell acts as the "caretaker" of the alveolar compartment.
What are type 1 and type 2 alveolar cells?
Typically, type 1 alveolar cells comprise the major gas exchange surface of the alveolus and are integral to the maintenance of the permeability barrier function of the alveolar membrane. Type 2 pneumocytes are the progenitors of type 1 cells and are responsible for surfactant production and homeostasis.
What do type 2 alveolar cells do?
Four major functions have been attributed to alveolar type II cells: (1) synthesis and secretion of surfactant; (2) xenobiotic metabolism; (3) transepithelial movement of water; and (4) regeneration of the alveolar epithelium following lung injury.
What is the function of type 2 cells?
Type II cells are defenders of the alveoli by secreting surfactant, keeping the alveolar space relatively free from fluid, serving as progenitor cells to repopulate the epithelium after injury, and providing important components of the innate immune system.
What do type 2 pneumocytes secrete?
Type 2 pneumocytes secrete surfactant Their nuclei are round and dark-staining, and their cytoplasm is rich in mitochondria and both rough and smooth endoplasmic reticulum.
What do type 1 pneumocytes produce?
The type 1 cells form a lining on the alveolar surface, and fasten the exchange of gases between alveoli and capillaries. It secretes surfactant proteins that reduce surface tension of the alveolar surface.
Which cell type produces surfactant quizlet?
Surfactant is a complex substance containing phospholipids and a number of apoproteins. This fluid is produced by the Type II alveolar cells, and lines the alveoli and smallest bronchioles.
What are the 3 types of cells in the alveoli?
Each alveolus consists of three types of cell populations: Type 1 pneumocytes. Type 2 pneumocytes. Alveolar macrophages.
What is the function of type 1 alveolar cells?
Pulmonary alveolar type I (AT1) cells cover more than 95% of alveolar surface and are essential for the air–blood barrier function of lungs. AT1 cells have been shown to retain developmental plasticity during alveolar regeneration.
Are type 2 alveolar cells the Clara cells?
A subset of Clara cells has been identified at the bronchiolar/alveolar junction that co-express Scgb 1a1 and an alveolar type 2 pneumocyte marker, Surfactant protein C (SftpC). This cell subset proliferates after lung injury and gives rise to both bronchiolar and alveolar epithelium in vitro (Kim, 2007).
What do Type 1 alveolar cells do?
Type I pneumocytes cover 95% of the internal surface of each alveolus. These cells are thin and squamous, ideal for gas exchange. They share a basement membrane with pulmonary capillary endothelium, forming the air-blood barrier where gas exchange occurs.
Which cells produce surfactant quizlet?
Surfactant is a complex substance containing phospholipids and a number of apoproteins. This fluid is produced by the Type II alveolar cells, and lines the alveoli and smallest bronchioles.
Which type of lung cells secretes pulmonary surfactant quizlet?
The alveolar cell that secretes pulmonary surfactant is the: alveolar type II cell.
What are type II pneumocytes?
Type II pneumocytes are identified as the synthesizing cells of the alveolar surfactant, which has important properties in maintaining alveolar and airway stability. Lung surfactant can reduce the surface tension and prevent alveolar collapse and the airway walls collapse.