Question

Describe the structure and function of the layers of the small intestine.

Answer 1

Intestinal wall is composed of four layers: from inside outward

1. Mucosa: This layer is further composed of 3 sublayers namely, epithelium, lamina propria and mucularis mucosa. Mucosa has Villus folding for increasing the surface area for absorption.

The epithelium is simple columnar epithelium having microvilli. this layer is responsible for absorption and secretion.

Lamina propria possess nerves, blood vessels and glands. It is responsible for holding the epithelial cells together to allowing the passage of blood vessels and nutrients. The lamina propria also serves as an important physical barrier which stops unwanted materials and organisms from gaining access to the body.

Muscularis mucosa

2. Submucosa: It is the Connective tissue layer, which contains blood vessels, lymphatics and the submucosal plexus. It possesses submucosal glands that secrete intestinal juices.

It also has Submucosal nerve plexus also called Auerbach plexus that stimulate the submucosal gland secretion.

3. Muscularis Externa:

It is the layer of smooth muscle namely Longitudinal and circular layers. They are responsible for the peristaltic movement of the small intestine.

4. serosa: It is composed of fibrous connective tissue. This layer provides protection and support.