Chapter 10: Respiratory System
Please familiarize yourself with these keywords before you start reading the chapter:
- Club cells (Clara cells)
- Cuboidal epithelial cells with apical microvilli located within and distal to bronchioles. Club cells are rich in metabolic enzymes (cytochrome P450 enzymes) and therefore serve a major role in the biotransformation of inhaled xenobiotics (see hepatocyte xenobiotic biotransformation).
- Goblet cells
- Columnar epithelial cells that produce and secrete mucin, a glycoprotein that is a major constituent of mucus. Histologically, goblet cells have swollen, basophilic to poorly staining cytoplasm (representing cytoplasmic mucin vesicles). Goblet cells are abundant within the respiratory tract and gastrointestinal tract.
- Nasal turbinates
- Scroll-like structures within the nasal cavity that are composed of a core of thin bone surrounded by connective tissue and lined by respiratory epithelium. The nasal turbinates function to help warm and humidify air and trap particulates.
- Olfactory epithelium
- Tall, pseudostratified sensory epithelium within the caudal portions of the nasal cavity that contains a population of chemoreceptor cells, olfactory receptor cells, that generate the sensation of smell.
- Respiratory epithelium
- A pseudostratified mucosal epithelium composed of columnar epithelial cells with apical cilia often admixed with goblet cells. This epithelium is characteristic of the upper respiratory tract (nasal cavity, sinuses, nasopharynx), eustachian tube, trachea, and large bronchi.
- Type I alveolar cells (type I pneumocytes)
- Flattened squamous epithelial cells that line pulmonary alveoli and facilitate gas exchange.
- Type II alveolar cells (type II pneumocytes)
- Polygonal to cuboidal epithelial cells within alveoli that secrete pulmonary surfactant and readily divide following tissue injury to type I alveolar cells.