Digestive system HAp -2nd, Slides of Pharmacy

Download Digestive system HAp -2nd and more Slides Pharmacy in PDF only on Docsity!

Digestive System (Unit II)

Presented by

Dr. Priyanka Arya

Associate Professor

Galgotias College of Pharmacy

The Layers of the GI tract The GI tract is composed of four layers. Each layer has different tissues and functions. From the inside out they are called:

1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa

• (^) Adventia layer (or serosa): Serosa consists of a secretory epithelial layer and a thin connective tissue layer that reduce the friction from muscle movements.
• (^) Muscularis: The muscularis externa is responsible for segmental contractions and peristaltic movement in the GI tract. These muscles cause food to move and churn together with digestive enzymes down the GI tract. The muscularis externa consists of an inner circular layer and a longitudinal outer muscular layer.

• (^) Submucosa: The submucosa is relatively thick , highly vascular , and serves the mucosa. The absorbed elements that pass through the mucosa are picked up from the blood vessels of the submucosa.
• (^) The submucosa also has glands and nerve plexuses. The submucosa lies under the mucosa and consists of fibrous connective tissue, separating the mucosa from the next layer , the muscularis externa.
• (^) Mucosa: The mucosa, composed of simple epithelium cells , is the innermost layer of the gastrointestinal (GI) tract. It is the absorptive and secretory layer of the GI tract.