Caecum - Anatomy & Physiology

Overview

Dog caecum, ileum and colon - © RVC 2008

Gibbon caecum and appendix- © RVC 2008

The cecum is a blind ending diverticulum of the large intestine and it exists at the junction of the ileum and the ascending colon. Its size and physiological importance varies between species. It is a site of microbial fermentation, absorption and transportation.

Structure

The caecum communicates with the ileum via the ileal orifice and with the colon via the caecocolic orifice. It consists of a base, body and apex. The apex is the blind-ending portion. It is attached to the ileum by a fold of peritoneum called the ileocaecal fold.

Function

1. Microbial Fermentation The contribution of this is species dependant. The products of fermentation are volatile fatty acids (VFAs).

2. Absorption VFAs that are produced are absorbed here.

3. Transportation Segmental contractions facilitate absorption and microbial activity. Every 3-5 minutes, segmentation is replaced by mass movements. This is similar to peristalsis, but large portions of the caecum contract simultaneously to move chyme into the colon.

Species Differences

Canine

In canine species, the caecum is on the right side of the abdomen. It is unique because it has no direct connection to the ileum. It is short and held in a spiral shape against the ileum by the ileocaecal fold. Little microbial fermentation takes place.

Ruminant

In the ruminant, the caecum is found on the right side of the abdomen, in the supraomental recess. The apex points caudally. It is relatively small and featureless, there are no taenia or haustra. Some microbial fermentation takes place.

Equine

A significant amount of fermentation takes place in the equine caecum. contains haustra & tenia, very large, and point cranially.

Porcine

The caecum is on the left side of the abdomen, with the apex pointing caudoventrally. It is cylindrical in shape and there are three taenia present. The ventral taenia provides the attachment for the ileocaecal fold. The lateral and medial taenia are free.

Histology

The caecum has no villi. The mucosa has mucous glands, the lamina muscularis has large lymphatic nodules and the submucosa has no glands.

Links

Click here for information on the pathology of the Small and Large Intestines

Click here for information on the Peyer's Patches

Caecum - Anatomy & Physiology Learning Resources
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