1. Slides last updated: March 2015 CRC: ANATOMY OF THE GASTROINTESTINAL TRACT

2. The wall of the GI tract is composed of four layers 1 1.Tortora GJ, et al. Principles of Anatomy and Physiology. 11 th Ed. Hoboken: John Wiley & Sons;2006:895-946. 4. Serosa 3. Muscularis 2. Submucosa 1. Mucosa Lumen GI tract wall

3. The wall of the GI tract is composed of four layers 1 1.Tortora GJ, et al. Principles of Anatomy and Physiology. 11 th Ed. Hoboken: John Wiley & Sons;2006:895-946. 1. Mucosa Mucous membrane that lines the lumen of the GI tract Further divided into the epithelium, lamina propria and muscularis mucosa 2. Submucosa Areolar connective tissue that binds the mucosa to the muscularis Contains blood and lymphatic vessels that receive the absorbed nutrients Also contains glands, lymphatic tissue and an extensive network of neurons

4. The wall of the GI tract is composed of four layers 1 1.Tortora GJ, et al. Principles of Anatomy and Physiology. 11 th Ed. Hoboken: John Wiley & Sons;2006:895-946. 3. Muscularis Contains either skeletal muscle for voluntary control of movement, or smooth muscle organised in two sheets of perpendicular fibres to generate involuntary contractions 4. Serosa Superficial layer of the GI tracts segments that are suspended in the abdominopelvic cavity Also called the visceral peritoneum Composed of areolar connective tissue and simple squamous epithelium

5. Stage is determined by how far the cancer has spread 1 1.American Cancer Society. Colorectal Cancer Detailed Guide, 2014. Available online from http://www.cancer.org/acs/groups/cid/documents/webcontent/003096-pdf.pdf, last accessed on 17/03/2015. Cancer progression Stage IA-B Cancer has grown through the muscularis mucosa or submucosa Stage IIA-C Cancer has grown through the muscularis propria, serosa, or through the colon or rectum wall Stage IIIA-C Cancer has grown through at least the muscularis mucosa, and has been found in nearby lymph nodes Stage IVA-B Cancer has grown through at least the muscularis mucosa and has spread to distant organs (metastasised) Stage 0 Cancer is in the mucosa only