GALT (Gut Associated Lymphoid tissue) is present in (AIPG – 2009)
References: Pg. 41, 77; Gray's Anatomy (39th Ed.) Gut Associated Lymphoid Tissue (GALT) is present in the Lamina propria (b) of Mucosa.
1. GALT serves as immunological barrier throughout the length of GI tract.
2. Peyer’s patches of ileum are under GALT and are mainly present in the lamina propria but may also extend into the Submucosa (a).
3. GALT & BALT (Bronchus Associated Lymphoid Tissue) come under a common term – MALT (Mucosa Associated Lymphoid Tissue).
4. -Lymphocytes are educated to recognize & destroy specific antigens in the MALT.
5. -MALT components are observed at other sites also like Mucosa of female reproductive tract.
6. Gut tube has 4 layers:
a. Mucosa b. Submucosa c. Muscularis externa d. Adventitia/Serosa
7. Lamina propria is a part of Mucosa and contains glands, blood vessels and components of immune system-GALT.
8. Muscularis mucosa (c) is also a part of Mucosa and mainly composed of smooth muscles. Its contraction moves the mucosa to facilitate secretion & absorption.
9. Submucosa (a) consists of mainly dense irregular connective tissue. It has neurovascular branches and some lymphatics also.
10. -The Meissner’s plexus is mainly a collection of parasympathetic neurons observed in submucosa only.
11. Adventitia/Serosa (d) are the outermost covering of GI tube. Adventitia is chiefly made up of connective tissue, whereas, serosa has the serous membrane made up of squamous epithelium.