Question

Circular muscle in the muscularis layer of the oesophagus

• A. decreases the length of the tract.
• B. increases the calibre of the tract.
• C. decreases the calibre of the tract.
• D. prevents the backflow of food.

Answer 1

Answer: (C), (D)

prevents the backflow of food.

Muscularis layer of the oesophagus has two muscles (outside to inside):

1. Longitudnal muscle: decreases the length of the tract.
2. Circular muscle: decreases the calibre/diameter of the gastrointestinal tract and prevents the backflow of the food. It plays role in the oesophageal phase of deglutition. Sequential contraction of the circular muscle results in a peristaltic wave that pushes the food toward the stomach.