A mucous cell, also known as a goblet cell, is a specialized epithelial cell found in various tissues throughout the body, particularly in the linings of organs and cavities exposed to the outside environment. These cells produce and secrete mucus, a sticky substance that plays a crucial role in protecting and lubricating these surfaces.
Key features of a mucous cell:
- Shape: They are typically columnar, resembling a truncated pyramid with a wider lumenal surface than serous cells.
- Secretory granules: Mucous cells accumulate secretory granules containing mucin, the main component of mucus, in their cytoplasm.
- Apical bleb: As the cell matures, these granules accumulate near the apical surface, pushing the nucleus towards the base of the cell and forming a characteristic apical bleb.
- Junctional complexes: Mucous cells are joined to their neighboring cells through junctional complexes and gap junctions, forming a cohesive epithelial lining.
Functions of mucous cells:
- Protection: Mucus acts as a barrier, protecting the underlying tissues from physical damage, microbial invasion, and harmful substances.
- Lubrication: Mucus facilitates smooth movement of substances, such as food in the digestive tract or air in the respiratory system.
- Trapping and removal: Mucus traps foreign particles like dust, bacteria, and allergens, helping to clear these substances from the body.
Examples of mucous cells in action:
- Respiratory system: Goblet cells in the airways secrete mucus that traps inhaled particles, aiding in their removal by cilia.
- Digestive system: Mucous cells in the stomach and intestines produce mucus that protects the lining from gastric acid and digestive enzymes.
- Reproductive system: Mucous cells in the cervix and vagina secrete mucus that plays a role in sperm transport and preventing infection.
Mucous cell metaplasia:
In some cases, epithelial cells that are not normally mucous cells can transform into mucous cells in response to various stimuli like inflammation or injury. This process, known as mucous cell metaplasia, can contribute to both protective and pathological changes in the body.
