Anatomy of the Gastrointestinal Tract Video

Video at a Glance

• The GI tract is composed of several layers.
• The innermost layer is the lumen, followed by the mucosa, the muscularis, and the serosa or mesentery layer.
• Peyer’s patches located in the lumen are lymph nodes lined with T lymphocytes and M cells which are responsible for immune surveillance and response.
• The layer between the muscularis and the mucosa is called the submucosa and is filled with blood vessels and submucosal glands which produce mucus.
• Most of the GI tract contains two muscle layers, longitudinal and circular, while the stomach has an extra layer, the oblique muscles that are responsible for churning.
• The gut has two layers of nerves called the enteric nervous system.
• The first layer is the myenteric plexus that controls the gut’s smooth muscles and directs peristalsis, while the second layer is the submucosal plexus, which controls secretions.