5.8 Overview of the Large Intestine, Rectum, and Anal Canal Flashcards
What are the Parts of the Large Intestine?
- The Ileocaecal Valve (Sphincter)
- The Caecum
- The Appendix
- The Ascending Colon
- The Transverse Colon
- The Descending Colon
- The Sigmoid Colon
What follows the Sigmoid Colon?
- The Rectum
2. The Anal Canal
What is the Ileocaecal Valve?
The Sphincter between the Ileum and the Caecum
What is the Caecum?
A Blind Sac which leads into the Ascending Colon
What is the Appendix?
An attachment to the Caecum, with no known function, but is a common site of infection (Appendicitis)
What is the Ascending Colon?
- The 1st Part of the Colon
- It lies on the Right Side of the Abdomen, lateral to the Small Intestines
- It is Retroperitoneal
- It leads to the Transverse Colon
What is the Transverse Colon?
- The 2nd Part of the Colon
- It lies Superiorly to the to the Small Intestines.
- It is Intraperitoneal
- It leads to the Descending Colon
What is the Descending Colon?
- The 3rd Part of the Colon
- It lies on the Left Side of the Abdomen, lateral to the Small Intestines
- It is Retroperitoneal
- It leads to the Sigmoid Colon
What is the Sigmoid Colon?
- It is the Final Part of the Colon
- It lies on the Left Side of the Abdomen, Infero-laterally to the Small Intestines
- It is Intraperitoneal
- It leads to the Rectum
What is the Rectum?
- It is a Straight Muscular Tube between the Sigmoid Colon and the Anal Canal
- It has a Simple Columnar Epithelium
- It has a Thick Muscularis Externa
What is the Anal Canal?
- It is a short (2-3cm) Canal Between the Rectum and the Anus
- It changes from a Proximal Simple Columnar Epithelium to a Distal Stratified Squamous Epithelium
- It has a Thick Muscularis Externa
- It has a Portion of Skeletal Muscle
What is the name of the Thick Muscularis Externa in the Anal Canal?
The Internal Anal Sphincter
What is the name of the Skeletal Muscle in the Anal Canal?
The External Anal Sphincter
What is the Mucosal Layer of the Colon formed of?
Simple Columnar Epithelium
What is the Mucosal Layer of the Colon lined with?
Many Goblet Cells, in the Crypts