Ileum - Anatomy & Physiology

()Map ALIMENTARY SYSTEM (Map) SMALL INTESTINE

Introduction

The ileum is the terminal portion of the small intestine and continues from the jejunum. It opens into the caecum at the ileocaecal orifice. The intestinal epithelium is mainly absorptive, with much less digestion occuring compared to the duodenum and the jejunum.

Structure

• The boundary between the ileum and jejunum is arbitrarily distinguished by the position of the ileocaecal fold.
• It is more muscular and firmer than the jejunum.
• It terminates at the ileocaecocolic junction.

Vasculature

• The cranial mesenteric artery supplies blood to the ileum.
• see jejunum

Histology

• Peyer's Patches, part of the mucosal associated lymphoid tissue (MALT), are present throughout the ileum and ileocaecal junction.
• They exist within the lamina propria.
  • They contain B and T lymphocytes.
  • B lymphocytes exist in follicles.

Links

• Pathology of the Small and Large Intestines
• Peyer's Patches
• Ileum Revision Flashcards

Videos

• Pot 48 The Small and Large intestine of the Ruminant
• Pot 357 The Feline Abdomen