The four layers of the digestive tract are mucosa, submucosa, muscularis propria and the adventitia. The mucosa is made up of loose connective tissue and lubricates the passage of food along and protects it from digestive enzymes. The submucosa is a layer of dense irregular connective tissue and supports the mucosa and joins it to the muscular layer. The muscularis propria is made up of smooth muscle tissue and helps with continued peristalsis and the movement of digested material out of and along the gut. The adventitia is composed of loose connective tissue and is coated in mucus to prevent any friction damage from the intestine rubbing against other tissue.
