Small bowel mucosa

October 26, 2023

Small bowel mucosa is a thin layer of tissue that covers the inside of a part of the digestive tract called the small bowel (also called the small intestine). The small bowel is made up of three parts – the duodenum, jejunum, and ileum. It starts at the end of the stomach and ends at the colon (large bowel).

Small bowel mucosa is made up of specialized epithelial cells that connect together to form glands and a thin layer of connective tissue called lamina propria. Very small finger-like projections of mucosa called villi stick out from the inner surface of the small bowel. These villi allow the small bowel to absorb nutrients by increasing the surface area of the small bowel.

A wide variety of medical conditions can involve the mucosa on the inside of the small bowel. For example, gluten-sensitive enteropathy, or Celiac disease, damages the epithelial cells on the surface of the small bowel. Doctors will often take a sample of tissue in a procedure called a biopsy to look for this condition or to monitor response to a gluten-free diet. Patients who take non-steroidal anti-inflammatory medications, or who are infected with the bacteria Helicobacter pylori, may show changes in the small bowel called peptic duodenitis. Some types of cancer, such as adenocarcinoma and neuroendocrine tumours, also start from cells in the mucosa.

About this article

This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

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