a-short-review-of-histology

Large Intestine:

The large intestine includes the caecum (and appendix) ascending colon, transverse colon, descending colon, sigmoid colon, rectum and anal canal
Each part has a similar general morphology which conforms with the basic gut plan
The appendix and anal canal are, however, structurally distinct from the other parts of the large intestine and will be considered separately
In the rectum, absorbtion of nutrients takes place as well as the absorbtion of water and the formation of the faeces
In the large intestine, there are no villi
Intestinal glands are present
As in the small intestine, they indent into the underlying connective tissue from the surface epithelium
The luminal epithelium is a simple columnar epithelium consisting mainly of absorbtive cells with microvilli, interspersed with goblet cells
The proportion of goblet cells in the luminal epithelium lining the lumen increases towards the rectum
At the distal end of the alimentary canal the mucus has a role in lubricating the stools to ease their passage into the rectum

Micrograph of Large Intestine:

Micrograph of Large Intestine

Micrograph of Villi in the Small Intestine

There are no villi in the large intestine
In the micrograph of the large intestine, identify the long straight intestinal glands (the lumen of the large intestine is on the right)
In this preparation goblet cells are stained green
Notice how many there are
MM = muscularis mucosae