What type of epithelium lines the esophagus and why?

• A. Simple cuboidal epithelium; absorption
• B. Non-keratinized stratified squamous epithelium; it resists abrasion from food without keratinization
• C. Keratinized stratified squamous epithelium; waterproofing
• D. Simple columnar epithelium; secretion

Answer: (B)

The esophagus needs a lining that can withstand repeated rubbing and grinding by food, while staying moist for smooth passage. A non-keratinized stratified squamous epithelium provides multiple protective cell layers that resist abrasion without forming a hard, dry surface. This suits the moist mucosa of the esophagus and allows it to handle the mechanical wear of swallowing.

In contrast, simple cuboidal or simple columnar epithelia are more about secretion and absorption and lack the layered protection needed for heavy abrasion. Keratinized stratified squamous epithelium, while excellent at waterproofing skin, would create a dry, tough surface unsuitable for a moist interior surface like the esophagus.