Intestinal Wall

Question 1

What are the 4 layers of the intestinal wall?

Answer 1

1. Serosa
2. Smooth muscle layer (longitudinal & circular)
3. Submucosa
4. Mucosa (mucosal muscle, epithelial cells)

Question 2

State 4 facts regarding then purpose and function of the serosa.

Answer 2

• this forms the outermost layer of the intestinal wall
• made up of a thin layer of simple squamous epithelium
• secretes watery fluid, lubricates surface of intestine
• protects the intestine from friction between abdominal organs.

Question 3

State 4 facts regarding the purpose and function of the Smooth muscle layer.

Answer 3

• also called ‘muscularis’
• Sub-divided
• Inner-circular muscle layer, and outer longitudinal layer
• Contractions move food along and churn it with digestive enzymes.
• Circular muscle layer prevents food travelling backwards.
• Longitudinal layer shortens the tract.
• Peristalsis

Question 4

The submucosa is a relatively thick connective layer. State 3 other facts about this layer.

Answer 4

• Dense connective tissue
• Separates mucosa from the muscles
• Contains glands

Question 5

The mucosa is the innermost layer of the intestinal wall. State 4 other facts about the mucosa.

Answer 5

• This is the only layer that comes into contact with the food
• functions = absorption, and secretion
• made up of epithelial cells
• surrounds the lumen.