Question

What are the layers of the gastrointestinal tract? What are their functions?

Answer 1

Gastrointestinal tract (GI tract):

1. It is also known as the alimentary canal.
2. The GI tract starts with an anterior opening - the mouth – and ends with a posterior opening – the anus.
3. The pharynx, esophagus, oral cavity, stomach, small intestine, and large intestine are all part of it.

Layers of the gastrointestinal tract:

1. It has four layers.
2. The serosa comprises connective tissues and a thin mesothelium.
3. Smooth muscles make up the muscularis layer.
4. The sub-mucosal layer is formed of loose connective tissues.
5. The mucosa is the innermost layer that lines the alimentary canal's lumen.

Functions:

1. Serosa secretes a lubricating fluid to allow sliding motion between opposed surfaces.
2. Muscularis is responsible for peristaltic movement in the GI tract.
3. Sub-mucosal layer supports the mucosa.
4. Mucosa creates irregular folds in the stomach (rugae) and little finger-like folds in the small intestine (villi) that increase the surface area for absorption of food.