Structure and Function of the Gastrointestinal System

Question 1

What are the four principal layers, that the GIT is organised into?

Answer 1

• Mucosa
• Submucosa
• Muscularis
• Serosa

Question 2

What layers make up the mucosa?

Answer 2

• Made up of three layers:
• Epithelium since the mucosa is technically surrounded by an external environment
• The Lamina Propria which is our connective tissue which can then anchor the epithelia
• The Muscular Mucosae which is a very thin layer of smooth muscle. The explicit purpose of this is to allow some movement in the epithelium layer.

Question 3

What is the Submucosa made up of?

Answer 3

• Dense Irregular Connective Tissue, within that there are larger blood vessels and lymphatic vessels, these are going to feed in particular blood vessels, going to the mucosal layer with the capillary beds

but here we get those larger blood vessels what we also get are some of the glands that will be opening up or emptying into the lumen of our GIT and then finally we have the submucosal plexus which is the first part of the enteric nervous system so we actually have neurons and nerves down at this stage

Question 4

What are the layers to the Muscularis Externa?

Answer 4

Muscle:

• Circular Smooth Muscle
• Longitudinal Smooth muscle
• Myenteric plexus
  
  • Part of the enteric nervous system
  • Connects to submucosal plexus