Which epithelium lines most of the digestive tract and consists of a single layer of tall, column-shaped cells with nuclei near the base?

Which epithelium lines most of the digestive tract and consists of a single layer of tall, column-shaped cells with nuclei near the base?

• A. Simple columnar epithelium
• B. Simple squamous epithelium
• C. Stratified squamous epithelium
• D. Pseudostratified ciliated columnar epithelium

Answer: (A)

This question hinges on recognizing how epithelial tissue structure matches its function in the digestive tract. The lining of most of the digestive canal is simple columnar epithelium, which is a single layer of tall, column-shaped cells with nuclei near the base. This arrangement supports absorption and secretion: the tall cells provide a large cytoplasmic area for organelles involved in nutrient processing, and the apical surface often has microvilli to greatly increase surface area for nutrient uptake. Goblet cells within this layer secrete mucus to protect and lubricate the lining. Other options don’t fit the description as well. Simple squamous epithelium consists of thin, flat cells ideal for rapid diffusion, not the heavy absorptive and secretory tasks of the digestive tract. Stratified squamous epithelium has multiple cell layers and is suited for protection in areas subject to abrasion, like the mouth and esophagus. Pseudostratified ciliated columnar epithelium appears layered due to nuclei at different heights and is typical of much of the respiratory tract, not the digestive tract.

This question hinges on recognizing how epithelial tissue structure matches its function in the digestive tract. The lining of most of the digestive canal is simple columnar epithelium, which is a single layer of tall, column-shaped cells with nuclei near the base. This arrangement supports absorption and secretion: the tall cells provide a large cytoplasmic area for organelles involved in nutrient processing, and the apical surface often has microvilli to greatly increase surface area for nutrient uptake. Goblet cells within this layer secrete mucus to protect and lubricate the lining.

Other options don’t fit the description as well. Simple squamous epithelium consists of thin, flat cells ideal for rapid diffusion, not the heavy absorptive and secretory tasks of the digestive tract. Stratified squamous epithelium has multiple cell layers and is suited for protection in areas subject to abrasion, like the mouth and esophagus. Pseudostratified ciliated columnar epithelium appears layered due to nuclei at different heights and is typical of much of the respiratory tract, not the digestive tract.