Submucosal glands are present in the following pa of gastro intestinal tract:
The major distinguishing feature of this C-shaped first pa of the small intestine duodenum) is the presence of duodenal (Brunner's) glands in the submucosa. The mucous cells of these glands produce an alkaline secretion (pH 8.1-9.3) that enters the lumen through the crypts. It protects the duodenal lining from the acidity of the chyme and raises the luminal pH to optimize pancreatic enzyme activity. Ref: Paulsen D.F. (2010). Chapter 15. Digestive Tract. In D.F. Paulsen (Ed), Histology & Cell Biology: Examination & Board Review, 5e.
Duodenum
Colon
Anal canal
Stomach