Simple columnar epithelium

Simple columnar epithelium is a single layer of tall, rectangular cells with nuclei typically located near the base of the cells.^[1] 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.^[3]
• 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.^[5] 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.^[4]
• 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.^[7]

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.^[8]
• 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.^[2]