Club_cells
Club cells, also known as bronchiolar exocrine cells,[1] are low columnar/cuboidal cells with short microvilli, found in the small airways (bronchioles) of the lungs.[2] They were formerly known as Clara cells.
Club cells are found in the ciliated simple epithelium. These cells may secrete glycosaminoglycans to protect the bronchiole lining. Bronchiolar cells gradually increase in number as the number of goblet cells decrease.
One of the main functions of club cells is to protect the bronchiolar epithelium. They do this by secreting a small variety of products, including club cell secretory protein uteroglobin, and a solution similar in composition to pulmonary surfactant. They are also responsible for detoxifying harmful substances inhaled into the lungs. Club cells accomplish this with cytochrome P450 enzymes found in their smooth endoplasmic reticulum. Club cells also act as a stem cell, multiplying and differentiating into ciliated cells to regenerate the bronchiolar epithelium.[3]