Simple columnar epithelium is a single layer of tall, rectangular cells with nuclei typically located near the base of the cells. It is specialized for absorption, secretion, and protection and may contain specialized structures like microvilli or cilia.
Anatomy
- Cell Shape: Tall, column-like cells with a height greater than their width.
- Nucleus: Oval-shaped, located near the basal region of the cell.
- Special Features:
- Ciliated columnar cells: Found in regions where movement of substances is necessary, such as the respiratory tract and fallopian tubes.
- Non-ciliated columnar cells: Often feature microvilli to increase surface area for absorption, particularly in the gastrointestinal tract.
- Goblet cells: Specialized mucus-secreting cells interspersed within the epithelium.
Location
Simple columnar epithelium is commonly found lining organs involved in absorption, secretion, or movement of substances. Major locations include:
- Non-ciliated
- Lining of the stomach.
- Small intestine and large intestine (with microvilli for nutrient absorption).
- Gallbladder.
- Ciliated
- Fallopian tubes (to move the ovum).
- Bronchioles of the respiratory tract.
- Ependymal lining of the central nervous system.
Function
- Absorption: Facilitates the uptake of nutrients in the digestive tract.
- Secretion: Produces mucus (via goblet cells), enzymes, and other substances.
- Movement: Cilia help move substances, such as mucus in the respiratory tract or eggs in the fallopian tubes.
- Protection: Acts as a barrier against harmful substances and pathogens.
Clinical Significance
- Celiac Disease: Damage to the simple columnar epithelium in the small intestine, particularly the loss of microvilli, leads to impaired nutrient absorption.
- Chronic Bronchitis: Damage to the ciliated epithelium of the respiratory tract impairs mucus clearance, leading to chronic inflammation.
- Cancer: Adenocarcinomas can arise from simple columnar epithelium, especially in the gastrointestinal tract.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn’s disease and ulcerative colitis involve damage to the intestinal epithelium.
