What is the innermost layer of the digestive tract?

What is the innermost layer of the digestive tract?

• A. Serosa
• B. Mucosa
• C. Submucosa
• D. Muscularis externa

Answer: (B)

The innermost layer lining the digestive tract is the mucosa. This tunic directly faces the lumen and is specialized for secretion, absorption, and protection. It includes the epithelium, the underlying lamina propria (loose connective tissue with vessels and immune cells), and the muscularis mucosae (a thin layer of smooth muscle that helps form tiny folds to increase surface area). Outside the mucosa lies the submucosa, then the muscularis externa (inner circular and outer longitudinal muscle layers for peristalsis), and finally the serosa or adventitia on the outer surface.

The innermost layer lining the digestive tract is the mucosa. This tunic directly faces the lumen and is specialized for secretion, absorption, and protection. It includes the epithelium, the underlying lamina propria (loose connective tissue with vessels and immune cells), and the muscularis mucosae (a thin layer of smooth muscle that helps form tiny folds to increase surface area). Outside the mucosa lies the submucosa, then the muscularis externa (inner circular and outer longitudinal muscle layers for peristalsis), and finally the serosa or adventitia on the outer surface.