1. Layers Of The GI Tract

Question 1

What are the layers of the GI tract from innermost to outermost?

Answer 1

Mucosa
Submucosa
Muscularis (inner and outer)
Serosa

Question 2

What are the 3 layers of the mucosa?

Answer 2

Epithelial layer
Lamina propria
Muscularis mucosa

Question 3

What kind of barrier is the epithelial layer of the gut?

Answer 3

Selectively permeable barrier

Promotes absorption, produces hormones and produces mucus

Question 4

What does the lamina propria contain?

Answer 4

Lots of lymphoid nodules and macrophages
Produces antibodies (IgA - resistant to proteases)

Question 5

What makes up the muscularis mucosae?

Answer 5

Smooth muscle orientated in different directions

Question 6

What is the role of the muscularis mucosae?

Answer 6

Helps keep the epithelium in contact with gut contents to improve absorption and make all other processes more efficient, helps keep crypts contents dynamic

Question 7

What is the submucosa?

Answer 7

Dense connective tissue layer containing blood vessels, glands, lymphoid tissue and contains submucosal/Meisner’s plexus (enteric nervous system)

Question 8

What does the muscularis propria contain?

Answer 8

Inner circular muscle and outer longitudinal muscle

Allows peristalsis

Question 9

What is between the longitudinal muscle and circular muscle in the muscularis propria?

Answer 9

Myenteric plexus (enteric nervous system)

Question 10

What does the serosa contain?

Answer 10

Blood vessels
Lymphatic vessels
Adipose tissue