8th February 2024

GI tract structure

GI tract structure

Structure

The GI tract can be divided into multiple different layers. From inner to outer layers, these are:

• Epithelial cells (specialised in the role of either secretion or absorption, depending on the site of the GI tract)
• Lamina propria
• Muscularis mucosa (changes the surface area of the GI tract)
• Circular muscle (increases or decreases circumference of GI tract)
• Longitudinal muscle (increases or decreases length of GI tract)
• Submucosal plexus and Myenteric plexus (make up the enteric nervous system of the GI tract). The enteric nervous system coordinates and disseminates information from the sympathetic and parasympathetic systems.
  • Submucosal plexus- controls secretion and blood flow (via sensory input from chemoreceptors and mechanoreceptors in the GI tract).
  • Myenteric plexus- controls motility.

Image Source: Wikimedia Commons (2020). Layers of the GI Tract English, Licensed under a creative commons licence. Available for free at: https://upload.wikimedia.org/wikipedia/commons/3/31/Layers_of_the_GI_Tract_english.svg (Accessed: 4 January 2024).