Layers of Digestive Tract

Question 1

Mucosa

Answer 1

• Inner most layer closest to ingested food
• 3 Sublayers - epithelium, lamina propria, muscularis mucosae
• Specialised cells that produce digestive enzymes, absorb nutrients and secrete mucus
• the mucus lubricates and protects the digestive tract

Question 2

Submucosa

Answer 2

• Dense layer of connective tissue
• Outside the Mucosa
• Contains blood vessels, lymphatic vessels and nerve fibres
• Allows the exchange of waste, nutrients, and signals between the digestive tract and the rest of the body
• Contains glands that secrete substances into the lumen.

Question 3

Muscularis Externa

Answer 3

• Thick layer of smooth muscle
• Peristalsis
• 2 sublayers - Inner most layer & Outer longitudinal layer
  Orientation of layers allows construction and shortening of digestive tract

Question 4

Serosa

Answer 4

• Outermost layer of digestive tract
• Connective tissue that anchors the tract to the surrounding structures
• Provides a protective barrier
• In ABDOMINAL CAVITY, covered by smooth slippery membrane called PERITONEUM
• Peritoneum reduces friction between digestive tract and surrounding organs
  Regions outside cavity, serosa is replaced by Adventitia