Brunner's glands

Brunner's glands (or duodenal glands) are compound tubular submucosal glands found in that portion of the duodenum which is above the hepatopancreatic sphincter (also known as the sphincter of Oddi). The main function of these glands is to produce a mucus-rich alkaline secretion i.e. mucous (containing bicarbonate) in order to:

• Protect the duodenum from the acidic content of chyme (which is neutralized by the bicarbonate in the duodenal glands' secretions)
• Provide an alkaline condition for the intestinal enzymes to be active, thus enabling absorption to take place
• Lubricate the intestinal walls

They also secrete urogastrone, which inhibits parietal and chief cells of the stomach from secreting acid and their digestive enzymes. This is another form of protection for the duodenum.

Structure

Brunner's glands are found in the submucosa of the duodenum, which distinguishes them from the majority of other gastrointestinal glands, including the gastric and intestinal glands, which are in the mucosa. They are most numerous near the pylorus. They secrete their contents into the intestinal glands.

Function

The function of Brunner's glands is to produce an alkaline secretion (containing bicarbonate) which:

• Helps to neutralize gastric acid in the chyme
• Provides an alkaline environment for the pancreatic enzymes to function optimally
• Lubricates the intestinal walls to aid the passage of chyme

Clinical significance

Hyperplasia of Brunner's glands (Brunner's gland hyperplasia) can lead to the formation of a Brunner's gland adenoma, a type of non-cancerous tumor. These adenomas are relatively rare and typically benign. They can cause obstruction and bleeding, but are typically asymptomatic unless they become large.

See also

• Gastrointestinal tract
• Duodenum
• Pylorus
• Gastric acid
• Chyme