Correct option is D
Club cells (formerly known as Clara cells) are non-ciliated cuboidal epithelial cells present in the bronchioles of the lungs. These cells play an essential role in protecting the respiratory tract by secreting various defense markers, enzymes, and surfactants. They also act as progenitor cells, aiding in the repair and regeneration of the bronchiolar epithelium.
Key Functions of Club Cells:
- Secretion of protective proteins and surfactants: Club cells produce Club Cell Secretory Protein (CCSP), which has anti-inflammatory properties and helps protect the lung.
- Detoxification of harmful substances: They contain cytochrome P450 enzymes, which help detoxify airborne toxins.
- Stem cell function: Club cells serve as progenitor cells that can regenerate ciliated and non-ciliated bronchiolar epithelial cells.
- Maintenance of bronchiolar integrity: They secrete components that maintain the lining of the small airways.
- Involvement in immune defense: They release secretory proteins that help modulate immune responses.
Additional Information
Option (1) Goblet Cells (Incorrect):
- Goblet cells are mucin-producing cells found in the respiratory epithelium. They secrete mucus to trap dust and microbes but do not serve as progenitor cells or detoxify harmful substances.
Option (2) Basal Cells (Incorrect):
- Basal cells are stem cells found in the trachea and bronchi (not bronchioles). They help regenerate the airway epithelium but do not secrete protective proteins like Club cells.
Option (3) Langerhans Cells (Incorrect):
- Langerhans cells are dendritic immune cells found in the skin and mucosa. They are involved in antigen presentation but are not epithelial cells of the bronchioles.
